Neuroactive 13,24-cyclo-18,21-dinorcholanes and structurally related pentacylic steroids

ABSTRACT

Novel pentacyclic steroids and pentacyclic D-homosteroids comprising: (i) the tetracyclic steroid ring system or tetracyclic D-homosteroid ring system, respectively; (ii) a C(3) substituent selected from the group consisting of (a) a hydroxyl or carboxyl in the α-configuration and (b) a sulfate or other negatively charged moiety; and (iii) a fused fifth ring, the fused fifth ring comprising a hydrogen bond acceptor, and (a) in the case of the pentacyclic steroid the C(13) and C(17) carbons, or (b) in the case of the pentacyclic D-homosteroid the C(13) and C(17a) carbons, having utility as anesthetics and in the treatment of disorders relating to GABA function and activity.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No. 10/856,314, filed May 28, 2004, and issued as U.S. Pat. No. 7,781,421, which claims benefit of U.S. provisional patent application Ser. No. 60/474,152, filed May 29, 2003, the entire contents of which are incorporated herein by reference in its entirety.

This invention was made with Government support under NIH Grant #5 PO1 GM47969 awarded by the National Institutes of Health. The Government has certain rights in the invention.

BACKGROUND OF THE INVENTION

The present invention is directed to novel pentacyclic steroids and novel pentacyclic D-homosteroids that have utility as anesthetics and in the treatment of disorders relating to GABA function and activity.

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter of the central nervous system. GABA activates two types of receptors, the inotropic GABA_(A) and the metabotropic GABA_(B) receptor. Activation of the GABA_(B) receptor by GABA causes hyperpolarization and a resultant inhibition of neurotransmitter release. The GABA_(A) receptor subtype regulates neuronal excitability and rapid mood changes, such as anxiety, panic, and stress response. GABA_(A) receptors are coupled to chloride ion channels; activation of the receptor induces increased inward chloride ion flux, resulting in membrane hyperpolarization and neuronal inhibition. Drugs that stimulate GABA_(A) receptors, such as benzodiazepines and barbiturates, have anticonvulsive effects (by reducing neuronal excitability and raising the seizure threshold) as well as anxiolytic and anesthetic effects. Recently, the effect of steroids on GABA_(A) receptors has been demonstrated. As a result, researchers are pursuing the discovery and synthesis of neuroactive steroids that act as anesthetics and/or serve to provide treatment for disorders related to GABA function.

In addition to anesthetic properties, neuroactive steroids may be used to treat disorders related to GABA function. For example, neuroactive steroids may be used as sedative-hypnotics. Progesterone, for example, exhibits benzodiazepine-like actions, inducing reduced sleep latency and increased non-REM sleep with only small changes in slow wave and REM sleep. Further, systemic administration of GABA-enhancing steroids has demonstrated anticonvulsant effects in animals. In addition, drugs that enhance GABA responses are often used to treat anxiety in humans. Thus, it might be expected that GABA-potentiating steroids would exhibit anxiolytic effects. In addition to uses as sedative-hypnotics, anticonvulsants, and anxiolytics, neuroactive steroids may be used to treat depression. Accumulating evidence suggests that patients with major depression have decreased levels of GABAergic neurosteroids, and that certain treatments for depression alter levels of these steroids. Although GABA is not typically thought to play a critical role in the biology of depression, there is evidence that low GABAergic activity may predispose to mood disorders. Finally, inhibition of NMDA receptors and enhancement of GABA_(A) receptors appear to play important roles in mediating the acute effects of ethanol in the nervous system. Recent studies suggest that GABAergic neurosteroids may be involved in some of the pharmacological effects of ethanol and that neuroactive steroids may be useful in treating ethanol withdrawal.

An alternative to developing GABAergic anesthetics is to focus on steroids that inhibit NMDA receptors. However, steroids that inhibit NMDA receptors often block GABA_(A) receptors as well, resulting in complex effects on CNS excitability. Neuroactive steroids containing a 3β-sulfate group inhibit GABA_(A) receptors non-competitively. These agents act by enhancing GABA_(A) receptor desensitization and display different degrees of enantioselectivity. These compounds may be useful as memory enhancers and in reversing the anesthetic effects of compounds that potentiate GABA at GABA_(A) receptors.

SUMMARY OF THE INVENTION

Among the various aspects of the present invention, therefore, is the provision of neuroactive 13,24-cyclo-18,21-dinorcholanes, and structurally related pentacyclic steroids and pentacyclic D-homosteroids, which potentiate the effects of GABA at GABA_(A) receptors useful for producing anesthesia or treating disorders related to GABA function such as insomnia, mood disorders, convulsive disorders, anxiety, or symptoms of ethanol withdrawal. Another aspect of the present invention is the provision of neuroactive 13,24-cyclo-18,21-dinorcholanes, and structurally related pentacyclic steroids and pentacyclic D-homosteroids that inhibit the effect of GABA at GABA_(A) receptors useful for memory enhancement and reversing the effects of compounds that potentiate GABA at GABA_(A) receptors.

Briefly, therefore, the present invention is directed to pentacyclic steroids and pentacyclic D-homosteroids comprising:

(i) the tetracyclic steroid ring system or tetracyclic D-homosteroid ring system, respectively;

(ii) a C(3) substituent selected from the group consisting of (a) a hydroxyl or carboxyl in the α-configuration and (b) a sulfate or other negatively charged moiety; and

(iii) a fused fifth ring, the fused fifth ring comprising a hydrogen bond acceptor, and

(a) in the case of the pentacyclic steroid the C(13) and C(17) carbons, or (b) in the case of the pentacyclic D-homosteroid the C(13) and C(17a) carbons,

wherein the tetracyclic steroid ring system corresponds to Formula (I)

and the tetracyclic D-homosteroid ring system corresponds to Formula (II)

Other objects and features of the present invention will be in part apparent and in part pointed out hereafter.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying figures where:

FIG. 1 shows two current traces (chloride currents) (FIGS. 1A and 1B) and two tables (FIGS. 1C and 1D) demonstrating the effect of cyclosteroids on electrophysiological responses to GABA in oocytes. In particular, FIG. 1A and FIG. 1B depict current traces for application of GABA to GABA receptors in the absence of cyclosteroids and in the presence of certain cyclosteroids; compound 35a (FIG. 1A) and compound 35b (FIG. 1B) and reference compound 1a (FIG. 1A) and compound 1b (FIG. 1B). FIG. 1C shows a table of chloride current versus specific compounds, which summarizes the effects of certain cyclosteroids tested at 500 nM against the response to 2 μM GABA alone (dotted line denotes the normalized response to GABA alone). FIG. 1D depicts a similar summary for the 51β-reduced series.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In general, the present invention is directed to pentacyclic steroids and D-homosteroids. The pentacyclic steroids comprise the tetracyclic ring system of Formula (I) and the pentacyclic D-homosteroids comprise the tetracyclic ring system of Formula (II):

In addition, the pentacyclic steroids comprise a fifth fused ring, sometimes identified herein as the “E” ring, the fifth fused ring comprising the carbon atoms at the C(13) and C(17) positions of Formula (I). Similarly, the pentacyclic D-homosteroids comprise a fifth fused ring, sometimes identified herein as the “E” ring comprising the carbon atoms at the C(13) and C(17a) positions. The pentacyclic steroids or pentacyclic D-homosteroids further comprise an E ring hydrogen bond acceptor.

In one embodiment, the compound is a pentacyclic steroid wherein each of rings A, B, C, and D of Formula (I) are saturated and the E ring is a 5- or 6-membered carbocyclic ring. Further, the E ring may be saturated. Alternatively, at least one pair of ring atoms of the E ring share a double bond. While the E ring may be fully saturated or partially unsaturated, the E ring hydrogen bond acceptor is selected from the group consisting of keto (═O), cyano (CN), acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond (that is, a carbon-carbon alkene bond between two E ring carbon atoms), and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. Typically, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene (═CH₂), methoxy (—OCH₃), acetyl (—C(O)CH₃), ═CHCN, ═CHC(O)CH₃, and an E ring alkene bond. Additionally, the E ring may comprise substituents selected from the group consisting of halo and alkyl. Further, for any of the above variations, the hydroxyl or carboxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group. For example, when the E ring is saturated and the hydrogen bond acceptor is keto, cyano, methylene, methoxy, acetyl, ═CHCN, or ═CHC(O)CH₃, the hydroxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group. Preferable linking groups include methylene, ethylene, methoxy, and ethoxy. Alternatively, when at least one pair of ring atoms of the E ring share a double bond and the hydrogen bond acceptor is keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, or an E ring alkene bond, the hydroxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group.

In another embodiment, the compound is a pentacyclic steroid wherein at least one pair of ring atoms comprising rings A, B, C, and D of Formula (I) share a double bond and the E ring is a 5- or 6-membered carbocyclic ring. Further, the E ring may be saturated. Alternatively, at least one pair of ring atoms of the E ring share a double bond. While the E ring may be fully saturated or partially unsaturated, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. Typically, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, and an E ring alkene bond. Additionally, the E ring may comprise substituents selected from the group consisting of halo and alkyl. Further, for any of the above variations, the hydroxyl or carboxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group. For example, when the E ring is saturated and the hydrogen bond acceptor is keto, cyano, methylene, methoxy, acetyl, ═CHCN, or ═CHC(O)CH₃, the hydroxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group. Preferable linking groups include methylene, ethylene, methoxy, and ethoxy. Alternatively, when at least one pair of ring atoms of the E ring share a double bond and the hydrogen bond acceptor is keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, or an E ring alkene bond, the hydroxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group.

In another embodiment, the compound is a pentacyclic D-homosteroid wherein each of rings A, B, C, and D of Formula (II) are saturated and the E ring is a 5- or 6-membered carbocyclic ring. Further, the E ring may be saturated. Alternatively, at least one pair of ring atoms of the E ring share a double bond. While the E ring may be fully saturated or partially unsaturated, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. Typically, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, and an E ring alkene bond. Additionally, the E ring may comprise substituents selected from the group consisting of halo and alkyl. Further, for any of the above variations, the hydroxyl or carboxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group. For example, when the E ring is saturated and the hydrogen bond acceptor is keto, cyano, methylene, methoxy, acetyl, ═CHCN, or ═CHC(O)CH₃, the hydroxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group. Preferable linking groups include methylene, ethylene, methoxy, and ethoxy. Alternatively, when at least one pair of ring atoms of the E ring share a double bond and the hydrogen bond acceptor is keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, or an E ring alkene bond, the hydroxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group.

In yet another embodiment, the compound is a pentacyclic D-homosteroid wherein at least one pair of ring atoms comprising rings A, B, C, and D of Formula (II) share a double bond and the E ring is a 5- or 6-membered carbocyclic ring. Further, the E ring may be saturated. Alternatively, at least one pair of ring atoms of the E ring share a double bond. While the E ring may be fully saturated or partially unsaturated, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. Typically, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, and an E ring alkene bond. Additionally, the E ring may comprise substituents selected from the group consisting of halo and alkyl. Further, for any of the above variations, the hydroxyl or carboxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group. For example, when the E ring is saturated and the hydrogen bond acceptor is keto, cyano, methylene, methoxy, acetyl, ═CHCN, or ═CHC(O)CH₃, the hydroxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group. Preferable linking groups include methylene, ethylene, methoxy, and ethoxy. Alternatively, when at least one pair of ring atoms of the E ring share a double bond and the hydrogen bond acceptor is keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, or an E ring alkene bond, the hydroxyl in the α-configuration at C(3) may be directly bonded to the C(3) position or bonded via a linking group.

In a preferred embodiment, the compound is a pentacyclic steroid comprising the tetracyclic steroid ring system, Formula (I), wherein each of rings A, B, C, and D of Formula (I) are fully saturated, the E ring is a 6-membered carbocyclic ring, the E ring hydrogen bond acceptor is an E ring alkene bond or is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, and an epoxide; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl, and the hydroxyl or carboxyl group is directly bonded to C(3). Alternatively, the hydroxyl or carboxyl group is bonded to C(3) via a linking group as defined for any of the previous embodiments.

In another preferred embodiment, the compound is a pentacyclic steroid comprising the tetracyclic steroid ring system, Formula (I), wherein at least one pair of ring atoms comprising rings A, B, C, and D share a double bond, the E ring is a 6-membered carbocyclic ring, the E ring hydrogen bond acceptor is an E ring alkene bond or is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, and an epoxide; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl, and the hydroxyl or carboxyl group is directly bonded to C(3). Alternatively, the hydroxyl or carboxyl group is bonded to C(3) via a linking group as defined for any of the previous embodiments.

In another embodiment, the pentacyclic steroids or pentacyclic D-homosteroids comprise Formulae (I) or (II), respectively, and the steroids or D-homosteroids have the standard steroid or D-homosteroid stereochemical configuration (8β,9α,10β,13β,14α). In this embodiment, the hydrogen at C(5), if present, may be in either the α-configuration or the β-configuration.

In another embodiment, the pentacyclic steroids or pentacyclic D-homosteroids of the present invention correspond to Formula (A)

wherein

R₂ is selected from the group consisting of hydrogen, alkoxy, and substituted or unsubstituted morpholine;

R_(3a) is hydroxy or carboxyl;

R_(3b) is hydrogen, alkyl, alkenyl, or alkynyl optionally substituted with halo, hydroxy, or substituted or unsubstituted aryl;

R₅ is α- or β-hydrogen;

R₁₀ is hydrogen or C₁₋₄ alkyl;

R₁₅ is hydrogen or oxo;

R₆, R₁₁ and R₁₂ are independently hydrogen or oxo;

L_(3a) is selected from the group consisting of a bond, C₁₋₃ alkyl, heterosubstituted C₁₋₃ alkyl, or alkoxy;

X₄-X₅-X₆ is selected from the group consisting of

X₉-X₁₁-X₁₂ is selected from the group consisting of

X₄₀ is a bond or a carbon atom; and

E is a 5- or 6-membered carbocyclic ring, comprising a hydrogen bond acceptor.

In one embodiment where the compounds correspond to Formula (A), X₄₀ is a bond. In this embodiment the carbocyclic ring, E, may be in the β-configuration in relation to the C and D rings. Further, the E ring hydrogen bond acceptor may be an E ring alkene bond or may be selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. Preferably, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, and an E ring alkene bond. In certain preferred embodiments, the hydrogen bond acceptor is keto, cyano, or ═CHCN. While the E ring may be as defined above for this embodiment, R₂ may be selected from the group consisting of hydrogen and substituted or unsubstituted morpholine. Preferably, R₂ is hydrogen. While the E ring and R₂ may be as defined above for this embodiment, L_(3a) may be a bond, methylene, ethylene, methoxy or ethoxy and R_(3a) may be hydroxyl. Alternatively, L_(3a) may be a bond, methylene, ethylene, methoxy or ethoxy and R_(3a) may be carboxyl. L_(3a) is preferably a bond. In certain instances of this embodiment, X₄-X₅-X₆ may be

and X₉-X₁₁-X₁₂ may be

Further, R_(3b) may be hydrogen or ethynyl substituted with alkyl or optionally substituted aryl. R_(3b) is preferably hydrogen or ethynyl substituted with phenyl substituted with amino, dimethylamino, hydroxyl, carboxyl, or alkoxy. Still further, in this embodiment, R₁₀ may be hydrogen or β-methyl.

In another embodiment where the compounds correspond to Formula (A), X₄₀ is carbon. In this embodiment, the carbocyclic ring, E, may be in the β-configuration in relation to the C and D rings. Further, the E ring hydrogen bond acceptor may be an E ring alkene bond or may be selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. Preferably, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, and an E ring alkene bond. In certain preferred embodiments, the hydrogen bond acceptor is keto, cyano, or ═CHCN. While the E ring may be as defined above for this embodiment, R₂ may be selected from the group consisting of hydrogen and substituted or unsubstituted morpholine. Preferably, R₂ is hydrogen. While the E ring and R₂ may be as defined above for this embodiment, L_(3a) may be a bond, methylene, ethylene, methoxy or ethoxy and R_(3a) may be hydroxyl. Alternatively, L_(3a) may be a bond, methylene, ethylene, methoxy or ethoxy and R_(3a) may be carboxyl. L_(3a) is preferably a bond. In certain instances of this embodiment, X₄-X₅-X₆ may be

and X₉-X₁₁-X₁₂ may be

Further, R_(3b) may be hydrogen or ethynyl substituted with alkyl or optionally substituted aryl. R_(3b) is preferably hydrogen or ethynyl substituted with phenyl substituted with amino, dimethylamino, hydroxyl, carboxyl, or alkoxy. Still further, in this embodiment, R₁₀ may be hydrogen or β-methyl.

In a preferred embodiment, the compounds correspond to Formula (A), X₄₀ is a bond or carbon, R₂ is hydrogen, R_(3b) is hydrogen, R₁₀ is β-methyl, L_(3a) is a bond, and E is a 6-membered carbocyclic ring wherein the E ring hydrogen bond acceptor is an E ring alkene bond or is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. When the E ring hydrogen bond acceptor comprises an epoxide ring, the epoxide ring comprises two carbon atoms of the E ring, each in the alpha position relative to each other, and an oxygen atom.

In another embodiment of the present invention, the compounds correspond to Formula (B)

wherein

R_(3a) is hydroxyl or carboxyl;

R₅ is α- or β-hydrogen; and

E is as previously defined for any of the above embodiments.

In yet another embodiment, the compounds of the present invention correspond to Formula (C)

wherein

R₅ is α- or β-hydrogen;

R₅₀ is selected from the group consisting of hydrogen, keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂ and an epoxide; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl, provided that when R₅₀ is hydrogen, at least one pair of E ring atoms share a double bond; and

E is a 6-membered carbocyclic ring wherein the dashed lines represent optional double bonds provided E comprises no more than 2 double bonds and provided each carbon ring atom of E is sp² or sp³ hybridized.

In one embodiment where the compounds correspond to Formula (C) and the E ring is in the β-configuration in relation to the C and D rings, R₅ may be α- or β-hydrogen and the E ring may be saturated or partially unsaturated. While the E ring and R₅ may be as defined above for this embodiment, R₅₀ is typically selected from the group consisting of hydrogen, keto, cyano, methylene, methoxy, acetyl, ═CHCN, and ═CHC(O)CH₃. In a preferred embodiment, R₅₀ is keto, cyano, or ═CHCN.

In another embodiment where the compounds correspond to Formula (C), the compound is selected from the group consisting of

In another embodiment, the compounds of the present invention correspond to Formula (D)

wherein

R₅ is α- or β-hydrogen;

R₅₀ is selected from the group consisting of hydrogen, keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, and an epoxide; where X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl, provided that when R₅₀ is hydrogen, at least one pair of E ring atoms share a double bond; and

E is a 5-membered carbocyclic ring wherein the dashed lines represent optional double bonds provided E comprises no more than 2 double bonds and each carbon ring atom of E ring is sp² or sp³ hybridized.

In one embodiment where the compounds correspond to Formula (D), the E ring is in the β-configuration in relation to the C and D rings. In this embodiment, R₅ may be α- or β-hydrogen and the E ring may be saturated or partially unsaturated. While the E ring and R₅ may be as defined above for this embodiment, R₅₀ is typically selected from the group consisting of hydrogen, keto, cyano, methylene, methoxy, acetyl, ═CHCN, and ═CHC(O)CH₃. In a preferred embodiment, R₅₀ is ═O, CN, or ═CHCN.

In another embodiment where the compounds correspond to Formula (D), the compound is selected from the group consisting of

In still another embodiment, the compounds of the present invention are pentacyclic steroids and pentacyclic D-homosteroids comprising:

(i) the tetracyclic steroid ring system, Formula (I) or tetracyclic D-homosteroid ring system, Formula (II), respectively;

(ii) a negatively charged substituent at physiological pH at C(3); and

(iii) a fused fifth ring, the fused fifth ring comprising a hydrogen bond acceptor, and (a) in the case of the pentacyclic steroid the C(13) and C(17) carbons, or (b) in the case of the pentacyclic D-homosteroid the C(13) and C(17a) carbons. In this embodiment, the negatively charged substituent at C(3) is typically selected from the group consisting of sulfate, carboxylate, phosphate, phosphonate, and combinations thereof, while rings A, B, C, D, and the fifth fused ring (the “E” ring) and all substituents are as previously defined for any of the above embodiments. In particular, each ring A, B, C, and D may be saturated or, alternatively, at least two of the ring atoms share a double bond. Further, the E ring may be a 5- or 6-membered carbocyclic fully saturated ring or, alternatively, at least one pair of ring atoms of the E ring share a double bond. As described previously for other embodiments, the E ring hydrogen bond acceptor may be selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; where X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. Typically, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, or an E ring alkene bond.

In a preferred embodiment, the compound is a pentacyclic steroid comprising the tetracyclic steroid ring system, Formula (I), wherein each of rings A, B, C, and D of Formula (I) are saturated or, alternatively, at least one pair of ring atoms comprising rings A, B, C, and D of Formula (I) share a double bond, the E ring is a 6-membered carbocyclic ring, the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; where X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl, and the negatively charged substituent at C(3) is a sulfate or carboxylate group.

Steroids having the general Formula (A) may be obtained by the methods described in the examples. The starting material for the compounds of Formula (A) may be obtained using the reaction conditions set forth in Example 1 or a similar process. Generally, cyanoketone (compound 8a of Example 1) was prepared from the 20-ketosteroid 6a (Example 1) in two steps (40%). The 20-keto group was then protected with ethylene glycol to give compound 9a (83%), and this compound was reacted with DIBALH in toluene at room temperature to yield aldehyde 10a. As described for the preparation of a different 13,24-cyclo-18,21-dinorchol-22-en-20-one, treatment of aldehyde 10a with aqueous HCl removed the ketal protecting group and affected a Robinson annulation to yield the cyclosteroid 11a (57% from steroid 9a). Hydrogenation of the 22-en-20-one 11a gave the 20-one 2a (91%).

The compounds of Formula (A) of the present invention are useful for potentiating GABA at GABA_(A) receptors thereby inducing anesthesia or treating disorders related to GABA function (i.e., insomnia, mood disorders, convulsive disorders, anxiety or symptoms of ethanol withdrawal) in mammals, including humans, and are preferably administered in the form of a pharmaceutical composition comprising an effective amount of a compound of the instant invention in combination with at least one pharmaceutically or pharmacologically acceptable carrier. The carrier, also known in the art as an excipient, vehicle, auxiliary, adjuvant, or diluent, is any substance that is pharmaceutically inert, confers a suitable consistency or form to the composition, and does not diminish the therapeutic efficacy of the compounds. The carrier is “pharmaceutically or pharmacologically acceptable” if it does not produce an adverse, allergic or other untoward reaction when administered to a mammal or human, as appropriate.

The pharmaceutical compositions containing the compounds of the present invention may be formulated in any conventional manner. Proper formulation is dependent upon the route of administration chosen. The compositions of the invention can be formulated for any route of administration so long as the target tissue is available via that route. Suitable routes of administration include, but are not limited to, oral, parenteral (e.g., intravenous, intraarterial, subcutaneous, rectal, subcutaneous, intramuscular, intraorbital, intracapsular, intraspinal, intraperitoneal, or intrasternal), topical (nasal, transdermal, intraocular), intravesical, intrathecal, enteral, pulmonary, intralymphatic, intracavital, vaginal, transurethral, intradermal, aural, intramammary, buccal, orthotopic, intratracheal, intralesional, percutaneous, endoscopical, transmucosal, sublingual and intestinal administration.

Pharmaceutically acceptable carriers for use in the compositions of the present invention are well known to those of ordinary skill in the art and are selected based upon a number of factors: the particular compound used, and its concentration, stability and intended bioavailability; the disease, disorder or condition being treated with the composition; the subject, its age, size and general condition; and the route of administration. Suitable carriers are readily determined by one of ordinary skill in the art (see, for example, J. G. Nairn, in: Remington's Pharmaceutical Science (A. Gennaro, ed.), Mack Publishing Co., Easton, Pa., (1985), pp. 1492-1517, the contents of which are incorporated herein by reference).

The compositions are preferably formulated as tablets, dispersible powders, pills, capsules, gelcaps, caplets, gels, liposomes, granules, solutions, suspensions, emulsions, syrups, elixirs, troches, dragees, lozenges, or any other dosage form that can be administered orally. Techniques and compositions for making oral dosage forms useful in the present invention are described in the following references: 7 Modern Pharmaceutics, Chapters 9 and 10 (Banker & Rhodes, Editors, 1979); Lieberman et al., Pharmaceutical Dosage Forms: Tablets (1981); and Ansel, Introduction to Pharmaceutical Dosage Forms 2nd Edition (1976).

The compositions of the invention for oral administration comprise an effective amount of a compound of the invention in a pharmaceutically acceptable carrier. Suitable carriers for solid dosage forms include sugars, starches, and other conventional substances including lactose, talc, sucrose, gelatin, carboxymethylcellulose, agar, mannitol, sorbitol, calcium phosphate, calcium carbonate, sodium carbonate, kaolin, alginic acid, acacia, corn starch, potato starch, sodium saccharin, magnesium carbonate, tragacanth, microcrystalline cellulose, colloidal silicon dioxide, croscarmellose sodium, talc, magnesium stearate, and stearic acid. Further, such solid dosage forms may be uncoated or may be coated by known techniques; e.g., to delay disintegration and absorption.

The compounds of the present invention are also preferably formulated for parenteral administration, e.g., formulated for injection via intravenous, intraarterial, subcutaneous, rectal, subcutaneous, intramuscular, intraorbital, intracapsular, intraspinal, intraperitoneal, or intrasternal routes. The compositions of the invention for parenteral administration comprise an effective amount of the compound in a pharmaceutically acceptable carrier. Dosage forms suitable for parenteral administration include solutions, suspensions, dispersions, emulsions or any other dosage form that can be administered parenterally. Techniques and compositions for making parenteral dosage forms are known in the art.

Suitable carriers used in formulating liquid dosage forms for oral or parenteral administration include nonaqueous, pharmaceutically-acceptable polar solvents such as oils, alcohols, amides, esters, ethers, ketones, hydrocarbons and mixtures thereof, as well as water, saline solutions, dextrose solutions (e.g., DW5), electrolyte solutions, or any other aqueous, pharmaceutically acceptable liquid.

Suitable nonaqueous, pharmaceutically-acceptable polar solvents include, but are not limited to, alcohols (e.g., α-glycerol formal, β-glycerol formal, 1,3-butyleneglycol, aliphatic or aromatic alcohols having 2-30 carbon atoms such as methanol, ethanol, propanol, isopropanol, butanol, t-butanol, hexanol, octanol, amylene hydrate, benzyl alcohol, glycerin (glycerol), glycol, hexylene glycol, tetrahydrofurfuryl alcohol, lauryl alcohol, cetyl alcohol, or stearyl alcohol, fatty acid esters of fatty alcohols such as polyalkylene glycols (e.g., polypropylene glycol, polyethylene glycol), sorbitan, sucrose and cholesterol); amides (e.g., dimethylacetamide (DMA), benzyl benzoate DMA, dimethylformamide, N-(β-hydroxyethyl)-lactamide, N,N-dimethylacetamide, 2-pyrrolidinone, 1-methyl-2-pyrrolidinone, or polyvinylpyrrolidone); esters (e.g., 1-methyl-2-pyrrolidinone, 2-pyrrolidinone, acetate esters such as monoacetin, diacetin, and triacetin, aliphatic or aromatic esters such as ethyl caprylate or octanoate, alkyl oleate, benzyl benzoate, benzyl acetate, dimethylsulfoxide (DMSO), esters of glycerin such as mono, di, or tri-glyceryl citrates or tartrates, ethyl benzoate, ethyl acetate, ethyl carbonate, ethyl lactate, ethyl oleate, fatty acid esters of sorbitan, fatty acid derived PEG esters, glyceryl monostearate, glyceride esters such as mono, di, or tri-glycerides, fatty acid esters such as isopropyl myristrate, fatty acid derived PEG esters such as PEG-hydroxyoleate and PEG-hydroxystearate, N-methylpyrrolidinone, pluronic 60, polyoxyethylene sorbitol oleic polyesters such as poly(ethoxylated)₃₀₋₆₀ sorbitol poly(oleate)₂₋₄, poly(oxyethylene)₁₅₋₂₀ monooleate, poly(oxyethylene)₁₅₋₂₀ mono 12-hydroxystearate, and poly(oxyethylene)₁₅₋₂₀ mono ricinoleate, polyoxyethylene sorbitan esters such as polyoxyethylene-sorbitan monooleate, polyoxyethylene-sorbitan monopalmitate, polyoxyethylene-sorbitan monolaurate, polyoxyethylene-sorbitan monostearate, and Polysorbate 20, 40, 60 or 80 from ICI Americas, Wilmington, Del., polyvinylpyrrolidone, alkyleneoxy modified fatty acid esters such as polyoxyl 40 hydrogenated castor oil and polyoxyethylated castor oils (e.g., CREMOPHOR EL solution or CREMOPHOR RH 40 solution), saccharide fatty acid esters (i.e., the condensation product of a monosaccharide (e.g., pentoses such as ribose, ribulose, arabinose, xylose, lyxose and xylulose, hexoses such as glucose, fructose, galactose, mannose and sorbose, trioses, tetroses, heptoses, and octoses), disaccharide (e.g., sucrose, maltose, lactose and trehalose) or oligosaccharide or mixture thereof with a C₄-C₂₂ fatty acid(s)(e.g., saturated fatty acids such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid and stearic acid, and unsaturated fatty acids such as palmitoleic acid, oleic acid, elaidic acid, erucic acid and linoleic acid)), or steroidal esters); alkyl, aryl, or cyclic ethers having 2-30 carbon atoms (e.g., diethyl ether, tetrahydrofuran, dimethyl isosorbide, diethylene glycol monoethyl ether); glycofurol (tetrahydrofurfuryl alcohol polyethylene glycol ether); ketones having 3-30 carbon atoms (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone); aliphatic, cycloaliphatic or aromatic hydrocarbons having 4-30 carbon atoms (e.g., benzene, cyclohexane, dichloromethane, dioxolanes, hexane, n-decane, n-dodecane, n-hexane, sulfolane, tetramethylenesulfon, tetramethylenesulfoxide, toluene, dimethylsulfoxide (DMSO), or tetramethylenesulfoxide); oils of mineral, vegetable, animal, essential or synthetic origin (e.g., mineral oils such as aliphatic or wax-based hydrocarbons, aromatic hydrocarbons, mixed aliphatic and aromatic based hydrocarbons, and refined paraffin oil, vegetable oils such as linseed, tung, safflower, soybean, castor, cottonseed, groundnut, rapeseed, coconut, palm, olive, corn, corn germ, sesame, persic and peanut oil and glycerides such as mono-, di- or triglycerides, animal oils such as fish, marine, sperm, cod-liver, haliver, squalene, squalane, and shark liver oil, oleic oils, and polyoxyethylated castor oil); alkyl or aryl halides having 1-30 carbon atoms and optionally more than one halogen substituent; methylene chloride; monoethanolamine; petroleum benzine; trolamine; omega-3 polyunsaturated fatty acids (e.g., alpha-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, or docosahexaenoic acid); polyglycol ester of 12-hydroxystearic acid and polyethylene glycol (SOLUTOL HS-15, from BASF, Ludwigshafen, Germany); polyoxyethylene glycerol; sodium laurate; sodium oleate; or sorbitan monooleate.

Other pharmaceutically acceptable solvents for use in the invention are well known to those of ordinary skill in the art, and are identified in The Handbook of Pharmaceutical Excipients, (American Pharmaceutical Association, Washington, D.C., and The Pharmaceutical Society of Great Britain, London, England, 1968), Modern Pharmaceutics, (G. Banker et al., eds., 3d ed.)(Marcel Dekker, Inc., New York, N.Y., 1995), The Pharmacological Basis of Therapeutics, (Goodman & Gilman, McGraw Hill Publishing), Pharmaceutical Dosage Forms, (H. Lieberman et al., eds.,) (Marcel Dekker, Inc., New York, N.Y., 1980), Remington's Pharmaceutical Sciences (A. Gennaro, ed., 19th ed.)(Mack Publishing, Easton, Pa., 1995), The United States Pharmacopeia 24, The National Formulary 19, (National Publishing, Philadelphia, Pa., 2000), A. J. Spiegel et al., and Use of Nonaqueous Solvents in Parenteral Products, J. of Pharm. Sciences, Vol. 52, No. 10, pp. 917-927 (1963).

Preferred solvents include oils rich in triglycerides, for example, safflower oil, soybean oil or mixtures thereof, and alkyleneoxy modified fatty acid esters such as polyoxyl 40 hydrogenated castor oil and polyoxyethylated castor oils (e.g., CREMOPHOR EL solution or CREMOPHOR RH 40 solution). Commercially available triglycerides include INTRALIPID emulsified soybean oil (Kabi-Pharmacia Inc., Stockholm, Sweden), NUTRALIPID emulsion (McGaw, Irvine, Calif.), LIPOSYN II 20% emulsion (a 20% fat emulsion solution containing 100 mg safflower oil, 100 mg soybean oil, 12 mg egg phosphatides, and 25 mg glycerin per ml of solution; Abbott Laboratories, Chicago, Ill.), LIPOSYN III 2% emulsion (a 2% fat emulsion solution containing 100 mg safflower oil, 100 mg soybean oil, 12 mg egg phosphatides, and 25 mg glycerin per ml of solution; Abbott Laboratories, Chicago, Ill.), natural or synthetic glycerol derivatives containing the docosahexaenoyl group at levels between 25% and 100% by weight based on the total fatty acid content (DHASCO® (from Martek Biosciences Corp., Columbia, Md.), DHA MAGURO (from Daito Enterprises, Los Angeles, Calif.), SOYACAL, and TRAVEMULSION.

Additional minor components can be included in the compositions of the invention for a variety of purposes well known in the pharmaceutical industry. These components will for the most part impart properties which enhance retention of the compound at the site of administration, protect the stability of the composition, control the pH, facilitate processing of the compound into pharmaceutical formulations, and the like. Preferably, each of these components is individually present in less than about 15 weight % of the total composition, more preferably less than about 5 weight %, and most preferably less than about 0.5 weight % of the total composition. Some components, such as fillers or diluents, can constitute up to 90 wt. % of the total composition, as is well known in the formulation art. Such additives include cryoprotective agents for preventing reprecipitation of the steroid or D-homosteroid, surface active, wetting or emulsifying agents (e.g., lecithin, polysorbate-80, TWEEN 80, pluronic 60, polyoxyethylene stearate), preservatives (e.g., ethyl-p-hydroxybenzoate), microbial preservatives (e.g., benzyl alcohol, phenol, m-cresol, chlorobutanol, sorbic acid, thimerosal and paraben), agents for adjusting pH or buffering agents (e.g., acids, bases, sodium acetate, sorbitan monolaurate), agents for adjusting osmolarity (e.g., glycerin), thickeners (e.g., aluminum monostearate, stearic acid, cetyl alcohol, stearyl alcohol, guar gum, methyl cellulose, hydroxypropylcellulose, tristearin, cetyl wax esters, polyethylene glycol), colorants, dyes, flow aids, non-volatile silicones (e.g., cyclomethicone), clays (e.g., bentonites), adhesives, bulking agents, flavorings, sweeteners, adsorbents, fillers (e.g., sugars such as lactose, sucrose, mannitol, or sorbitol, cellulose, or calcium phosphate), diluents (e.g., water, saline, electrolyte solutions), binders (e.g., starches such as maize starch, wheat starch, rice starch, or potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropyl methylcellulose, sodium carboxymethyl cellulose, polyvinylpyrrolidone, sugars, polymers, acacia), disintegrating agents (e.g., starches such as maize starch, wheat starch, rice starch, potato starch, or carboxymethyl starch, cross-linked polyvinyl pyrrolidone, agar, alginic acid or a salt thereof such as sodium alginate, croscarmellose sodium or crospovidone), lubricants (e.g., silica, talc, stearic acid or salts thereof such as magnesium stearate, or polyethylene glycol), coating agents (e.g., concentrated sugar solutions including gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, or titanium dioxide), and antioxidants (e.g., sodium metabisulfite, sodium bisulfite, sodium sulfite, dextrose, phenols, and thiophenols).

Dosage from administration by these routes may be continuous or intermittent, depending, for example, upon the patient's physiological condition, whether the purpose of the administration is therapeutic or prophylactic, and other factors known to and assessable by a skilled practitioner.

Those with ordinary skill in administering anesthetics can readily determine dosage and regimens for the administration of the pharmaceutical compositions of the invention or titrating to an effective dosage for use in treating insomnia, mood disorders, convulsive disorders, anxiety or symptoms of ethanol withdrawal. It is understood that the dosage of the compounds will be dependent upon the age, sex, health, and weight of the recipient, kind of concurrent treatment, if any, frequency of treatment, and the nature of the effect desired. For any mode of administration, the actual amount of compound delivered, as well as the dosing schedule necessary to achieve the advantageous effects described herein, will also depend, in part, on such factors as the bioavailability of the compound, the disorder being treated, the desired therapeutic dose, and other factors that will be apparent to those of skill in the art. The dose administered to an animal, particularly a human, in the context of the present invention should be sufficient to effect the desired therapeutic response in the animal over a reasonable period of time. Preferably, an effective amount of the compound, whether administered orally or by another route, is any amount that would result in a desired therapeutic response when administered by that route. The dosage may vary depending on the dosing schedule, which can be adjusted as necessary to achieve the desired therapeutic effect. The most preferred dosage will be tailored to the individual subject, as is understood and determinable by one of ordinary skill in the art without undue experimentation.

In one embodiment, solutions for oral administration are prepared by dissolving the compound in any pharmaceutically acceptable solvent capable of dissolving a compound (e.g., ethanol or methylene chloride) to form a solution. An appropriate volume of a carrier which is a solution, such as CREMOPHOR EL solution, is added to the solution while stirring to form a pharmaceutically acceptable solution for oral administration to a patient. If desired, such solutions can be formulated to contain a minimal amount of, or to be free of, ethanol, which is known in the art to cause adverse physiological effects when administered at certain concentrations in oral formulations.

In another embodiment, powders or tablets for oral administration are prepared by dissolving a compound in any pharmaceutically acceptable solvent capable of dissolving the compound (e.g., ethanol or methylene chloride) to form a solution. The solvent can optionally be capable of evaporating when the solution is dried under vacuum. An additional carrier can be added to the solution prior to drying, such as CREMOPHOR EL solution. The resulting solution is dried under vacuum to form a glass. The glass is then mixed with a binder to form a powder. The powder can be mixed with fillers or other conventional tabletting agents and processed to form a tablet for oral administration to a patient. The powder can also be added to any liquid carrier as described above to form a solution, emulsion, suspension or the like for oral administration.

Emulsions for parenteral administration can be prepared by dissolving a compound in any pharmaceutically acceptable solvent capable of dissolving the compound (e.g., ethanol or methylene chloride) to form a solution. An appropriate volume of a carrier which is an emulsion, such as LIPOSYN II or LIPOSYN III emulsion, is added to the solution while stirring to form a pharmaceutically acceptable emulsion for parenteral administration to a patient. If desired, such emulsions can be formulated to contain a minimal amount of, or to be free of, ethanol or CREMOPHOR solution, which are known in the art to cause adverse physiological effects when administered at certain concentrations in parenteral formulations.

Solutions for parenteral administration can be prepared by dissolving a compound in any pharmaceutically acceptable solvent capable of dissolving the compound (e.g., ethanol or methylene chloride) to form a solution. An appropriate volume of a carrier which is a solution, such as CREMOPHOR solution, is added to the solution while stirring to form a pharmaceutically acceptable solution for parenteral administration to a patient. If desired, such solutions can be formulated to contain a minimal amount of, or to be free of, ethanol or CREMOPHOR solution, which are known in the art to cause adverse physiological effects when administered at certain concentrations in parenteral formulations.

If desired, the emulsions or solutions described above for oral or parenteral administration can be packaged in IV bags, vials or other conventional containers in concentrated form and diluted with any pharmaceutically acceptable liquid, such as saline, to form an acceptable concentration prior to use as is known in the art.

DEFINITIONS

The term “steroid” as used herein describes an organic compound containing in its chemical nucleus the perhydrocyclopentanophenanthrene ring.

The term “D-homosteroid” as used herein describes an organic compound containing in its chemical nucleus the perhydrochrysene ring.

The term “hydrogen bond acceptor” as described herein generally describes a substance that receives hydrogen atoms from another substance, the donor. Examples of hydrogen bond acceptors include, but are not limited to the following: halogens, ═O, CN, ═CHCN, ═CH, ═CHC(O)CH₃, acyl, ═CHX₁, —OX₂ and an epoxide, where X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl, and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. A sp² hybridized carbon atom may also function as a hydrogen bond acceptor.

The term “saturated” as used herein describes the state in which all available valence bonds of an atom (especially carbon) are attached to other atoms.

The term “unsaturated” as used herein describes the state in which not all available valence bonds along the alkyl chain are satisfied; in such compounds the extra bonds usually form double or triple bonds (chiefly with carbon).

Unless otherwise indicated, the alkyl groups described herein are preferably lower alkyl containing from one to eight carbon atoms in the principal chain and up to 20 carbon atoms. They may be straight or branched chain or cyclic and include methyl, ethyl, propyl, isopropyl, butyl, hexyl and the like.

Unless otherwise indicated, the alkenyl groups described herein are preferably lower alkenyl containing from two to eight carbon atoms in the principal chain and up to 20 carbon atoms. They may be straight or branched chain or cyclic and include ethenyl, propenyl, isopropenyl, butenyl, isobutenyl, hexenyl, and the like.

Unless otherwise indicated, the alkynyl groups described herein are preferably lower alkynyl containing from two to eight carbon atoms in the principal chain and up to 20 carbon atoms. They may be straight or branched chain and include ethynyl, propynyl, butynyl, isobutynyl, hexynyl, and the like.

A “carboxyl” moiety as described herein is composed of a carbonyl group and a hydroxyl group bonded to a carbon atom, commonly shown as COOH or CO₂H.

The term “acyl,” as used herein alone or as part of another group, denotes the moiety formed by removal of the hydroxyl group from the —COOH group of an organic carboxylic acid, e.g., RC(O)— wherein R is R_(a), R_(a)O—, R_(a)S—, or R_(a)R_(b)N—, R_(a) and R_(b) are independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or heterocyclo and “—” denotes the point of attachment.

The terms “hydrocarbon” and “hydrocarbyl” as used herein describe organic compounds or radicals consisting exclusively of the elements carbon and hydrogen. These moieties include alkyl, alkenyl, alkynyl, and aryl moieties. These moieties also include alkyl, alkenyl, alkynyl, and aryl moieties substituted with other aliphatic or cyclic hydrocarbon groups, such as alkaryl, alkenaryl and alkynaryl. Unless otherwise indicated, these moieties preferably comprise 1 to 20 carbon atoms.

The “substituted hydrocarbyl” moieties described herein are hydrocarbyl moieties which are substituted with at least one atom other than carbon, including moieties in which a carbon chain atom is substituted with a hetero atom such as nitrogen, oxygen, silicon, phosphorous, boron, sulfur, or a halogen atom. These substituents include halogen, heterocyclo, alkoxy, alkenoxy, alkynoxy, aryloxy, hydroxy, protected hydroxy, keto, acyl, acyloxy, nitro, amino, amido, nitro, cyano, thiol, ketals, acetals, esters and ethers.

The term “aryl” as used herein alone or as part of another group denote optionally substituted homocyclic aromatic groups, preferably monocyclic or bicyclic groups containing from 6 to 12 carbons in the ring portion, such as phenyl, biphenyl, naphthyl, substituted phenyl, substituted biphenyl or substituted naphthyl. Phenyl and substituted phenyl are the more preferred aryl.

The terms “halogen” or “halo” as used herein alone or as part of another group refer to chlorine, bromine, fluorine, and iodine.

An “epoxide” moiety as described herein is an organic compound containing a reactive resulting from the union of an oxygen atom with two other atoms (usually carbon) that are joined in some other way.

As used herein, “Ac” means acetyl; “THF” means tetrahydrofuran, “NNHTs” means tosylhydrazone, “MOM” means methoxymethyl; “DMF” means dimethyl formamide, “DMSO” means dimethyl sulfoxide, “KHMDS” means potassium hexamethyldisilazane, “DBU” means 1,8-diazabicyclo[5.4.0]undec-7-ene; “DIBALH” means diisobutylaluminum hydride, and “HMPA” means hexamethylphosphoramide; “DEAD” means diethyl azodicarboxylate; “PCC” means pyridinium chlorochromate; “m-CPBA” means meta-chloroperbenzoic acid, and “NBS” means N-bromosuccinimide.

The following examples illustrate the invention.

EXAMPLE 1

EXAMPLE 2

EXAMPLE 3

EXAMPLE 4

EXAMPLE 5

EXAMPLE 6

EXAMPLE 7

EXAMPLE 8

EXAMPLE 9

EXAMPLE 10

EXAMPLE 11

EXAMPLE 12

EXAMPLE 13

EXAMPLE 14

EXAMPLE 15

EXAMPLE 16

EXAMPLE 17

EXAMPLE 18

EXAMPLE 19

EXAMPLE 20

EXAMPLE 21

EXAMPLE 22

EXAMPLE 23

EXAMPLE 24

EXAMPLE 25

Experimental Section for Examples 1-25

General Methods.

Melting points were determined on a Kolfer micro hot stage and are uncorrected. NMR spectra were recorded in CDCl₃ at 300 MHz (¹H) or 75 MHz (¹³C). IR spectra were recorded as films on a NaCl plate. Elemental analyses were carried out by M-H—W Laboratories, Phoenix, Ariz. Solvents were used either as purchased or dried and purified by standard methodology. Flash chromatography was performed using silica gel (32-63 μm) purchased from Scientific Adsorbents, Atlanta, Ga.

As set forth in Example 1, compounds 11a, 11b, 2a, and 2b may be prepared by first adding a cyano group at C(20) of (3α,5β)- or (3α,5β)-(3-acetyloxy)pregnan-20-one using acetone cyanohydrin. The cyano group at C(20) migrates to C(18) through the use of a free radical initiator, such as Pb(OA_(C))₄. The ketone at C(20) may then be converted to a ketal using any alcohol or 1,2- or 1,3-glycol. The cyano group may then be reduced to form an aldehyde group using a reducing agent, such as DIBALH. To form the carbocyclic E ring, a cyclization reaction may be carried out in acidic conditions (pH≦5.5) forming compounds 11a and 11b. Hydrogenation of these compounds yields compounds 2a and 2b, respectively.

As set forth in Example 2, compounds 3a, 3b, 2a, and 2b may be prepared by first introducing a double bond into the E ring. Depending upon the starting material, the first step may involve converting the oxo group on the E ring to NNHTs using p-toluenesulfonylhydrazine. The NNHTs group, if present, may then be eliminated in the presence of a strong base, such as n-butyllithium, thereby introducing a double bond into the E ring. Alternatively, the elimination may be carried out by converting the compound to the tolyslate sodium salt to eliminate hydrogen. The hydroxyl group at C(3) may then be protected using a protecting group that is stable in acid or base, such as methoxymethyl. Using, for example, diborane, a hydroxyl group may then be introduced in the E ring at positions C(20) or C(22). A mild oxidizing agent may then be used to convert the hydroxyl group to an oxo, while leaving the protecting group at C(3) intact. One example of such an oxidizing agent is pyridinium chlorochromate. Finally, the hydroxyl at C(3) may be deprotected, using almost any acid, yielding compounds 3a, 3b, 2a, and 2b.

As set forth in Example 3, compounds 21c, 22c, 4a and 4b may be prepared using compounds 11a and 11b as starting materials, respectively, by first introducing an epoxide ring into the E ring using a peroxide or peracid, such as hydrogen peroxide. Hydrazine or substituted hydrazine may then be used as part of an elimination reaction to form an unsaturated E ring possessing a hydroxyl group at C(23). Oxidation of the allylic alcohol using an oxidizing agent selective for oxidation of the carbon atoms adjacent to a double bond, such as MnO₂, may then proceed yielding compounds 21c and 22c. These compounds may then be converted by catalytic hydrogenation to yield compounds 4a and 4b.

As set forth in Example 4, compounds 30a and 30b may be prepared starting from compounds 11a and 11b, respectively, using isopropenyl acetate and an acid catalyst or sodium iodide, acetic anhydride, and a trialkylsilyl halide to form the dienol acetate. A borohydride, such as sodium borohydride, may then be used to remove the acetate group from the E ring. The alcohol may then be converted to an iodide group using a nucleophilic displacement reaction. After reduction with SmI₂, the compounds may be oxidized to introduce an oxo group into the E ring. Finally, a saponification reaction or an acid catalyzed reaction yields compounds 30a and 30b.

As set forth in Example 5, compounds 5a and 5b may be prepared starting from compounds 28a and 28b, respectively, by first forming an epoxide ring using a peroxide, such as m-chloroperbenzoic acid. The epoxide ring may then be opened with HI, HCl, HBr, or HF and the compound subjected to an oxidation reaction using a chromium reagent, such as Jones reagent. The resulting compound may then be subjected to base-catalyzed elimination, acid or base hydrolysis, and hydrogenation to yield compounds 5a and 5b.

As set forth in Example 6, compounds 39 and 40 may be prepared by first acylating the starting compound, 2a, with an acylating agent such as Ac₂O. Diethyl cyanophosphate may then be used, followed by SmI₂ to form the cyano group at C(20). Finally, the acetate group at C(3) may be removed to form compounds 39 and 40. Compounds 44 and 45 of Example 7 and compounds 49 and 50 of Example 8 may be prepared in the same manner.

As set forth in Example 9, compound 51 is prepared by converting the carbonyl of compound 2a into a double bond using, for example, the Witting reaction. Compound 52 of Example 10 and compound 53 of Example 11 may be prepared in the same manner.

As set forth in Example 12, compound 57 may be prepared by first protecting the C(3) hydroxyl of compound 2a with a group such as MOM or a silyl group. The carbonyl may then be modified using N-phenyltrifluoromethane sulfonamide. The triflate may then be converted to cyano and, finally, the C(3) hydroxyl group may be deprotected to yield compound 57.

As set forth in Example 13, compound 60 may be prepared by converting the hydroxyl group at C(20) into a leaving group, for example, by treating with MsCl, and then performing an elimination reaction under basic conditions yielding compound 60.

As set forth in Example 14, compound 61 may be prepared by removal of the acetate group at C(3) by hydrolysis or reduction of compound 28a.

As set forth in Example 15, compound 63 may be prepared by subjecting compound 54 to a Wittig reaction using (triphenylphosphoranylidene)acetonitrile and then removing the protecting group at C(3).

As set forth in Example 16, compounds 63 and 64 may be prepared by subjecting compound 2a to a Wittig reaction with (triphenylphosphoranyidene)acetonitrile.

As set forth in Example 17, compounds 67 and 68 may be prepared by reduction of the ketone group of compound 18a using a hydride reducing agent such as sodium borohydride to obtain compounds 65 and 66 and subsequent removal of the methyoxymethyl group by acid catalyzed hydrolysis.

As set forth in Example 18, compounds 69 and 70 are prepared by methylation of the hydroxyl group of compounds 65 and 66 followed by removal of the methoxymethyl group by acid catalyzed hydrolysis.

As set forth in Example 19, compounds 71 and 72 may be prepared by epoxidation of the double bond of compound 13a using a peracid such as meta-chloroperbenzoic acid.

As set forth in Example 20, compounds 73 and 74 may be prepared by epoxidation of the double bond of compound 51 using a peracid such as meta-chloroperbenzoic acid.

As set forth in Example 21, compounds 79 and 80 may be prepared from compound 18a by a Wittig reaction using ethyltriphenylphosphonium bromide to obtain the methyl-substituted olefin 75, hydroboration of the double bond of compound 75 to obtain the hydroxyl group present in compound 76, PCC oxidation of the hydroxyl group of compound 76 to give the ketone group shown in compounds 77 and 78 and removal of the methoxymethyl group by acid catalyzed hydrolysis to obtain compounds 79 and 80.

As set forth in Example 22, compound 83 may be prepared by bromination of a mixture of compounds 77 and 78 using a reagent such as N-bromosuccinimide, elimination of the bromine to form the double bond shown in compound 82 and removal of the methoxymethyl group by acid catalyzed hydrolysis to obtain compound 83.

As set forth in Example 23, compound 89 may be prepared from compound 84 by conversion of the carboxylic acid group to the corresponding acid chloride group and then reaction of this acid chloride with diazomethane to give the known compound 85. Compound 85 is then cyclized using Rh₂(OCOCF₃)₄ to give compound 86. The acetate group is hydrolyzed from compound 86 using base catalysis to give compound 87 and the beta configuration of the hydroxyl group in compound 87 is changed using a Mitsunobu reaction that yields compound 88 with a benzoate ester in the alpha configuration. The ester is hydrolyzed from compound 88 using base catalysis to yield compound 89.

As set forth in Example 24, compounds 94 and 95 may be prepared by bromination of compound 88 using a brominating reagent such a pyridinium tribromide to obtain compounds 90 and 91 that are then subjected to an elimination reaction to obtain compounds 92 and 93. Hydrolysis of the benzoate ester of compounds 92 and 93 under conditions of basic catalysis yields compounds 94 and 95.

As set forth in Example 25, compounds 96 and 97 may be prepared by subjecting compound 89 to a Wittig reaction with (triphenylphosphoranyidene)acetonitrile.

In addition, the hydrogen bond accepting groups on the E ring exemplified in Examples 1-25 may be converted into various other hydrogen bond accepting groups such as an epoxide, carboxy, thioester, alcohol, or ether. Generally, an epoxide ring may be formed from conversion of a ketone to the olefin intermediate, followed by treatment with peracid. A carboxy group may be formed from the hydrolysis of a cyano group. The C═ONH₂ hydrolyzes to COOH, which, if desired, can then be converted to an ester. A thioester may be formed from the accession from COOH. Ethers may be formed from the alkylation of oxygen.

(3α,5α)-3-(Acetyloxy)-20-hydroxypregnane-20-carbonitrile (7a)

Compound 7a was prepared using a reported procedure. (See, Mickova, R., et al., Isolation and the Structure of the Product of Cholesterol Biodegradation by the Mutant Mycobacterium sp. CCM 3529, Coll. Czech. Chem. Comm. 1985, 50:1110-1113). Et₃N (0.2 mL) was added to (3α,5α)-3-(acetyloxy)pregnan-20-one (6a, 1.0 g, 2.77 mmol) in acetone cyanohydrin (2 mL) at 50° C. The reaction mixture was slowly cooled to room temperature with stirring. After 3 h, water (5 mL) was added to the reaction mixture, and the white solid precipitate (mixture of compound 6a and 7a) was filtered and washed thoroughly with water, then dried under high vacuum at room temperature for 24 h. The precipitate was used without further purification.

An analytical sample of 7a was purified by column chromatography (silica gel; hexanes/EtOAc, 7:1) and obtained as white crystals: mp 192-195° C. (EtOAc-hexanes); ¹H NMR δ 0.81 (s, 3H, 19-CH₃), 1.00 (s, 3H, 18-CH₃), 1.62 (s, 3H, 21-CH₃), 2.05 (s, 3H, CH₃CO₂), 5.01 (m, 1H, CHOAc); ¹³C NMR δ 11.3, 13.0, 20.5, 21.5, 24.0, 25.0, 26.1, 28.2, 30.6, 31.8, 32.8 (2×C), 34.9, 35.8, 40.0, 40.2, 43.5, 54.1, 55.9, 59.1, 70.1, 71.7, 122.0 (CN), 170.7 (CO₂); IR ν_(max) 3389, 2924, 2231, 1701, 1281 cm⁻¹. Anal. (C₂₄H₃₇NO₃) C, H, N.

(3α,5α)-3-(Acetyloxy)-20-oxo-pregnane-18-carbonitrile (8a)

Compound 8a was prepared using a reported procedure. (See, Kalvoda, J., et al., Reactions of Steroid Hypoiodites. VII. 1,4-Shift of the Nitrile Group (18-Cyanopregnanes), Helv. Chim. Acta 1966, 49: 424-436) I₂ (1.6 g, 6.30 mmol) was added to a refluxing mixture of Pb(OAc)₄ (6.0 g, 13.5 mmol) and CaCO₃ (2 g, 20.0 mmol) in cyclohexane (200 mL). The purple solution was refluxed for 1 h and the mixture of compound 6a and 7a obtained in last step [prepared from 6a (1.0 g, 2.77 mmol)] was added. The reaction mixture was refluxed while irradiated with a 300 W tungsten lamp for 3 h and then cooled to room temperature. After filtration, the precipitate was washed thoroughly with ether. The combined filtrate was washed successively with 10% Na₂S₂O₃ and brine, and dried over Na₂SO₄. Removal of solvent under reduced pressure gave a residue which was purified by column chromatography (silica gel; hexanes/EtOAc, 4:1) to give compound 8a (400 mg, 40% from 6a) and recovered compound 6a (400 mg).

Compound 8a was obtained as a colorless oil: ¹H NMR δ 0.80 (s, 3H, 19-CH₃), 2.06 (s, 3H, CH₃CO₂), 2.29 (s, 3H, 21-CH₃), 2.70 (t, J=9.0 Hz, 1H, CHCOCH₃), 5.02 (m, 1H, CHOAc); ¹³C NMR δ 11.3, 16.4, 20.6, 21.5, 23.1, 24.0, 26.0, 28.0, 31.6, 32.5, 32.7, 32.7, 35.5, 35.7, 36.0, 39.8, 46.1, 53.7, 56.5, 62.0, 69.8, 118.1 (CN), 170.5 (CO₂), 208.7 (CO); IR ν_(max) 2933, 2249, 1732, 1704, 1245 cm⁻¹. Anal. (C₂₄H₃₅NO₃) C, H, N.

(3α,5α)-3-(Acetyloxy)-20,20-[1,2-ethanediylbis(oxy)]pregnane-18-carbonitrile (9a)

A mixture of compound 8a (1.93 g, 5.00 mmol), ethylene glycol (3.1 g, 50 mmol) and PPTS (0.64 g, 2.55 mmol, 30% W/W) in toluene (50 mL) was refluxed using a Dean-Stark apparatus under N₂ for 2 h. The reaction mixture was cooled to room temperature, washed with 10% NaHCO₃ and brine, and dried over Na₂SO₄. The solvent was removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 9:1) to give compound 9a (1.78 g, 83%).

Compound 9a was obtained as white crystals: mp 176-177° C. (EtOAc-hexanes); ¹H NMR δ 0.80 (s, 3H, 19-CH₃), 1.29 (s, 3H, 21-CH₃), 2.05 (s, 3H, CH₃CO₂), 2.27 (d, J=16.8 Hz, 1H, CH₂CN), 2.52 (d, J=16.8 Hz, 1H, CH₂CN), 4.04 (m, 4H, OCH₂CH₂O), 5.01 (m, 1H, CHOAc); ¹³C NMR δ 11.2, 16.7, 20.3, 21.4, 23.0, 23.2, 23.4, 25.9, 28.0, 31.4, 32.6 (2×C), 35.0, 35.6, 36.6, 39.7, 43.7, 53.7, 56.0, 56.3, 63.0, 63.7, 69.8, 110.8 (20-C), 119.8 (CN), 170.4 (CO₂); IR ν_(max) 2937, 2241, 1730, 1237 cm⁻¹. Anal. (C₂₆H₃₉NO₄) C, H, N.

(3α,5α)-20,20-[1,2-Ethanediylbis(oxy)]-3-hydroxypregnane-18-carboxaldehyde (10a)

Compound 9a (2.0 g, 4.66 mmol) in THF (120 mL) was cooled to −78° C. and DIBALH (1.0 M in toluene, 23.3 mL, 23.3 mmol) was added. The colorless solution was stirred at ambient temperature for 26 h and then cooled to 0° C. After H₂O (5 mL) was added dropwise to quench the reaction, the solvent was removed at room temperature. EtOAc (50 mL) and H₂O (20 mL) were added to the residue. Insoluble Al(OH)₃ was filtered through a pad of CELITE 545® and washed thoroughly with EtOAc. The combined filtrate was washed with water and dried over Na₂SO₄. Solvent removal under reduced pressure gave aldehyde 10a as a white solid that was partially characterized and immediately converted into cyclosteroid 11a. Aldehyde 10a had: ¹H NMR δ 0.77 (s, 3H, 19-CH₃), 1.29 (s, 3H, 21-CH₃), 3.85 (m, 4H, OCH₂CH₂O), 4.03 (m, 1H, CHOH), 9.82 (t, J=2.4 Hz, 1H, CHO); ¹³C NMR δ 11.1, 20.2, 22.9, 23.4, 23.5, 28.3, 28.9, 31.7, 32.0, 34.8, 35.7, 36.0, 36.3, 39.0, 40.2, 44.1, 54.1, 57.6, 57.7, 62.6, 64.0, 66.2, 111.1 (20-C), 204.9 (CHO).

(3α,5α)-3-Hydroxy-13,24-cyclo-18,21-dinorchol-22-en-20-one (11a)

A solution of aldehyde 10a in THF (100 mL) and aqueous HCl (4 N, 32 mL) was stirred under N₂ at room temperature for 16 h. THF was removed under reduced pressure. The residue was extracted with EtOAc. The combined EtOAc extracts were washed with 10% NaHCO₃ and brine, and dried over Na₂SO₄. After solvent removal under reduced pressure, the residue was purified by column chromatography (silica gel; CH₂Cl₂/EtOAc, 8:1) to give enone 11a (0.86 g, 57% from 9a).

Compound 11a was obtained as white crystals: mp 230-232° C. (EtOAc-hexanes); ¹H NMR δ 0.79 (s, 3H, 19-CH₃), 4.05 (m, 1H, CHOH), 5.96 (dd, J=3.0 Hz, J=9.9 Hz, 1H, CH═CHCO), 6.83 (m, 1H, CH═CHCO); ¹³C NMR δ 11.2, 20.3, 25.8, 26.2, 27.2, 28.3, 28.9, 32.0, 32.1, 33.9, 35.3, 35.8, 36.1, 39.0, 47.5, 53.7, 56.3, 57.7, 66.3, 127.4 (CH═CHCO), 148.3 (CH═CHCO), 202.3 (CO); IR ν_(max) 3429, 2924, 1666, 1444 cm⁻¹. Anal. (C₂₂H₃₂O₂) C, H.

(3α,5α)-3-Hydroxy-13,24-cyclo-18,21-dinorcholan-20-one (2a)

Enone 11a (328 mg, 1.0 mmol) was dissolved in EtOAc (50 mL) and hydrogenated (40 psi, H₂, 5% Pd/BaSO₄, 100 mg) for 1.5 h. The reaction mixture was filtered through a pad of CELITE 545 to remove catalyst and the solvent was removed under reduced pressure. The product was purified by column chromatography (silica gel; hexanes/EtOAc/CH₂Cl₂, 6:1:0.3) to give compound 2a (300 mg, 91%) as white crystals: mp 200-202° C. (EtOAc-hexanes); ¹H NMR δ 0.79 (s, 3H, 19-CH₃), 2.50 (m, 1H, CHCO), 4.04 (m, 1H, CHOH); ¹³C NMR δ 11.2, 20.3, 22.1 (2×C), 25.1, 27.0, 28.4, 29.0, 32.1, 32.2, 33.5, 35.2, 35.8, 36.1, 37.3, 39.0, 49.6, 53.9, 56.7, 61.5, 66.4, 215.6 (CO); IR ν_(max) 3548, 2928, 1701, 1253 cm⁻¹. Anal. (C₂₂H₃₄O₂) C, H.

(3α,5α)-13,24-Cyclo-18,21-dinorchol-20(22)-en-3-ol (13a)

To the solution of compound 2a (330 mg, 1.0 mmol) and p-toluenesulfonhydrazide (186 mg, 1.0 mmol) in MeOH (40 mL) was added 3 drops of 96% H₂SO₄. The reaction mixture was stirred at room temperature for 3-4 h and the MeOH was removed under reduced pressure. The residue was dissolved in EtOAc (50 mL) and washed with 10% NaHCO₃ and brine, and dried over Na₂SO₄. After solvent removal, hydrazone 12a was obtained and used without further purification or characterization.

n-BuLi (2.5 M in hexanes, 1.6 mL, 4 mmol) was added dropwise to the solution of hydrazone 12a (obtained from 1.0 mmol ketone 2a) in anhydrous THF (10 mL) under N₂ at 0° C. The orange solution was stirred overnight (14 h) at ambient temperature and quenched with water (0.4 mL) at 0° C. EtOAc (50 mL) was added and the mixture was washed with saturated aqueous NH₄Cl and brine, and dried over Na₂SO₄. After solvent removal under reduced pressure, the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) to give compound 13a (201 mg, 64% from ketone 2a).

Compound 13a was obtained as white crystals: mp 169-170° C. (hexanes); ¹H NMR δ 0.79 (s, 3H, 19-CH₃), 4.04 (m, 1H, CHOH), 5.55 (m, 1H, CH═), 5.76 (m, 1H, CH═); ¹³C NMR δ 11.2, 19.8, 20.2, 21.6, 24.7, 28.6, 29.1, 30.6, 32.3 (2×C), 33.2, 34.7, 35.9, 36.2, 39.3, 40.9, 46.6, 54.7, 56.1, 66.6, 124.4 (CH═), 130.9 (CH═); IR ν_(max) 3307, 3019, 2927, 1430, 1002 cm⁻¹. Anal. (C₂₂H₃₄O) C, H.

(3α,5α)-3-Methoxymethoxy-13,24-cyclo-18,21-dinorchol-20(22)-ene (14a)

Methoxy methylchloride (0.11 mL, 1.5 mmol) was added to compound 13a (158 mg, 0.5 mmol) and N,N-diisopropyl ethylamine (0.44 mL, 5 mmol) in CH₂Cl₂ (20 mL). The resultant solution was stirred at room temperature for 24 h. The solvent was partially removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) to give compound 14a (170 mg, 95%) as white crystals: mp 77-78° C. (hexanes); ¹H NMR δ 0.80 (s, 3H, 19-CH₃), 3.37 (s, 3H, CH₃O), 3.83 (m, 1H, CHOCH₂), 4.66 (m, 2H, OCH₂O), 5.56 (m, 1H, CH═), 5.76 (m, 1H, CH═); ¹³C NMR δ 11.4, 19.8, 20.2, 21.6, 24.7, 26.4, 28.7, 30.6, 32.3, 32.9, 33.3, 33.7, 34.7, 36.0, 39.9, 40.9, 46.6, 54.7, 55.1, 56.2, 71.7, 94.6 (OCH₂O), 124.4 (CH═), 130.9 (CH═); IR ν_(max) 3016, 2927, 1455, 1043 cm⁻¹. Anal. (C₂₄H₃₈O₂) C, H.

(3α,5α)-3-Hydroxy-13,24-cyclo-18,21-dinorcholan-22-one (3a)

BH₃ (1.0 M in THF, 1.59 mL, 1.59 mmol) was added to compound 14a (190 mg, 0.53 mmol) in anhydrous THF (20 mL) under N₂ at 0° C. The resultant solution was stirred at room temperature for 3.5 h and cooled to 0° C. Water (0.1 mL) was added to quench the reaction followed by aq. NaOH (3N, 3.0 mL) and 30% H₂O₂ (3.0 mL). The reaction mixture was stirred at ambient temperature for 1.5 h and extracted with CH₂Cl₂. The combined CH₂Cl₂ extracts were washed with brine until the pH was neutral and then dried over Na₂SO₄. After solvent removal under reduced pressure, the residue (a mixture of two pairs of diastereomers of 15a and 16a) was used without further purification or characterization.

NaOAc (130 mg, 1.59 mmol) and PCC (228 mg, 1.06 mmol) were added to the solution of compounds 15a and 16a in CH₂Cl₂ (30 mL). The reaction mixture was stirred at room temperature for 2 h and Et₂O (50 mL) was added. The mixture was filtered through a pad of CELITE 545 and washed thoroughly with ether. Solvent was removed from the combined filtrate to give a mixture of ketones 17a and 18a which was dissolved in CH₃OH (12 mL). Then, 37% aqueous HCl (4 mL) was added. The solution was stirred at room temperature for 1 h and MeOH was removed under reduced pressure. EtOAc (30 mL) was added to the residue and the solution was washed with water, 10% NaHCO₃, brine, and dried over Na₂SO₄. Solvent removal under reduced pressure gave ketones 3a and 2a which were separated by column chromatography (silica gel; EtOAc/CH₂Cl₂, 1:15) to give ketone 3a (90 mg, 51% from 14a) and recovered compound 2a (58 mg, 33% from 14a).

Compound 3a was obtained as white crystals: mp 195-197° C. (EtOAc-hexanes); ¹H NMR δ 0.79 (s, 3H, 19-CH₃), 2.39 (m, 1H, CH₂CO), 2.54 (dd, J=6.0 Hz, J=14.4 Hz, 1H, CH₂CO), 4.05 (m, 1H, CHOH); ¹³C NMR δ 11.2, 20.4, 23.3, 23.6, 27.7, 28.4, 29.0, 32.0, 32.2, 32.7, 35.6, 35.8, 36.2, 36.9, 39.1, 41.2, 41.5, 48.9, 54.4, 55.6, 66.4, 213.4 (CO); IR ν_(max) 3308, 2918, 1712, 1449, 1007 cm⁻¹. Anal. (C₂₂H₃₄O₂) C, H.

(3α,5α,22S,23S)-22,23-Epoxy-3-hydroxy-13,24-cyclo-18,21-dinorcholan-20-one (19a) and (3α,5α,22R,23R)-22,23-Epoxy-3-hydroxy-13,24-cyclo-18,21-dinorcholan-20-one (19b)

A mixture of MeOH (5 mL), 30% H₂O₂ (1.5 mL) and aqueous NaOH (4N, 0.25 mL) was added to a solution of enone 11a (100 mg, 0.30 mmol) in 1:1 MeOH and 1,4-dioxane (20 mL) at 0° C. The resultant solution was stirred at 0° C. for 3-4 h. EtOAc (30 mL) was added and the organic phase was washed with water and brine, and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue which was purified by column chromatography (silica gel; hexanes/EtOAc/CH₂Cl₂, 4:1:0.2) to give a mixture of compound 19a and 19b (1.8:1) 90 mg (86%). Analytical samples were obtained by HPLC separation (silica gel; hexanes/EtOAc, 6:1).

Compound 19a was obtained as white crystals: mp 238-240° C. (EtOAc-hexanes); ¹H NMR δ 0.81 (s, 3H, 19-CH₃), 3.15 (d, J=3.3 Hz, 1H, epoxide H-22), 3.55 (s, 1H, epoxide H-23), 4.05 (m, 1H, CHOH); ¹³C NMR δ 11.2, 20.1, 20.9, 24.7, 27.6, 28.3, 29.0, 32.0, 32.1, 35.1, 35.7, 36.1, 36.4, 39.0, 42.0, 51.8, 53.7, 54.8, 56.4, 57.0, 66.4, 207.1 (CO); IR ν_(max) 3551, 2925, 1691 cm⁻¹. Anal. (C₂₂H₃₂O₃) C, H.

Compound 19b was obtained as white crystals: mp 194-195° C. (EtOAc-hexanes); ¹H NMR δ 0.79 (s, 3H, 19-CH₃), 3.23 (d, J=3.6 Hz, 1H, epoxide H-22), 3.55 (t, J=3.6 Hz, 1H, epoxide H-23), 4.05 (m, 1H, CHOH); ¹³C NMR δ 11.3, 20.2, 24.2, 25.5, 26.0, 28.3, 29.0, 32.0, 32.2, 35.1, 35.8, 36.1, 36.4, 39.0, 51.5, 53.6, 54.5, 56.7, 57.9, 59.2, 66.4, 209.2 (CO); IR ν_(max) 3435, 2926, 1699 cm⁻¹. Anal. (C₂₂H₃₂O₃) C, H.

(3α,5α,23S)-13,24-Cyclo-18,21-dinorchol-20(22)-ene-3,23-diol (21a) and (3α,5α,23R)-13,24-Cyclo-18,21-dinorchol-20(22)-en-3,23-diol (21b)

The mixture of epoxides 19a and 19b (68 mg, 0.20 mmol), NH₂NH₂.xH₂O (x˜1.5, 136 μL, 2.4 mmol) and AcOH (2.35 μL) in MeOH (4 mL) was refluxed for 2 h. Water (20 mL) was added and the product was extracted with CH₂Cl₂. The combined CH₂Cl₂ extracts were washed with water until the pH was neutral and then dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue which was purified by column chromatography (silica gel; CH₂Cl₂/hexanes/EtOAc, 1:1:0.2) to give compound 21a (26 mg, 40%) and compound 21b (14 mg, 22%).

Compound 21a was obtained as white crystals: mp 94-96° C. (EtOAc-hexanes); ¹H NMR δ 0.82 (s, 3H, 19-CH₃), 4.05 (m, 1H, CHOH), 4.22 (m, 1H, CH═CHCHOH), 5.72 (m, 1H, CH═CHCHOH), 5.97 (m, 1H, CH═CHCHOH); ¹³C NMR δ 11.3, 20.4, 25.3, 28.1, 28.6, 29.1, 30.4, 32.2, 32.3, 34.8, 35.7, 35.9, 36.3, 39.3, 40.0, 46.6, 54.7, 57.0, 64.8, 66.6, 125.6 (CH═), 133.9 (CH═); IR ν_(max) 3359, 3018, 2927, 1446, 1003 cm⁻¹.

Compound 21b was obtained as white crystals: mp 215-217° C. (EtOAc-hexanes); ¹H NMR δ 0.81 (s, 3H, 19-CH₃), 4.05 (m, 1H, CHOH), 4.28 (m, 1H, CH═CHCHOH), 5.57 (d, J=10.2, 1H, CH═CHCHOH), 5.85 (m, 1H, CH═CHCHOH); ¹³C NMR δ 11.3, 20.2, 24.9, 28.5, 29.0, 29.8, 31.0, 32.2, 32.3, 34.2, 34.7, 35.9, 36.2, 39.2, 44.2, 46.4, 54.6, 56.4, 65.9, 66.6, 128.4 (CH═), 132.6 (CH═); IR ν_(max) 3328, 3019, 2926, 1446, 1003 cm⁻¹.

(3α,5α)-3-Hydroxy-13,24-cyclo-18,21-dinorchol-20(22)-en-23-one (21c)

Activated MnO₂ (420 mg, 4.83 mmol) was added to a mixture of compounds 21a and 21b (60 mg, 0.18 mmol) in CHCl₃ (20 mL). The reaction mixture was stirred at room temperature for 48 h. The MnO₂ was removed by filtration and the CHCl₃ was removed under reduced pressure. The residue was purified by column chromatography (silica gel; CH₂Cl₂/EtOAc, 20:1) to give compound 21c (28 mg, 47%) and a recovered mixture of compounds 21a and 21b (27 mg).

Compound 21c was obtained as white crystals: mp 209-210° C. (EtOAc-hexanes); ¹H NMR δ 0.78 (s, 3H, 19-CH₃), 2.37 (d, J=16.2 Hz, 1H, CH₂CO), 4.05 (m, 1H, CHOH), 5.90 (d, J=9.9 Hz, 1H, C(O)CH═CH), 6.96 (dd, J=5.4, J=9.9 Hz, 1H, C(O)CH═CH); ¹³C NMR δ 11.3, 19.7, 26.3, 28.3, 29.0, 29.4, 32.0, 32.2, 34.2, 34.8, 35.8, 36.2, 38.0, 39.1, 47.3, 47.4, 54.2, 56.1, 66.5, 127.2 (C(O)CH═CH), 152.1 (C(O)CH═CH), 200.3 (CO); IR ν_(max) 3467, 2926, 1664, 1451, 1004 cm⁻¹. Anal. (C₂₂H₃₂O₂) C, H.

(3α,5α)-3-Hydroxy-13,24-cyclo-18,21-dinorcholan-23-one (4a)

Compound 21c (28 mg, 0.085 mmol) was dissolved in MeOH (10 mL) and hydrogenated (40 psi, H₂, 5% Pd/BaSO₄, 9 mg) for 2 h. The reaction mixture was filtered through a pad of CELITE 545 to remove catalyst and the solvent was removed under reduced pressure. The product was purified by column chromatography (silica gel; hexanes/EtOAc, 4:1) to give compound 4a (26 mg, 94%).

Compound 4a was obtained as white crystals: mp 185-186° C. (EtOAc-hexanes); ¹H NMR δ 0.76 (s, 3H, 19-CH₃), 4.04 (m, 1H, CHOH); ¹³C NMR δ 11.2, 19.8, 24.3, 24.9, 25.2, 28.3, 29.0, 31.9, 32.2, 34.2, 34.9, 35.8, 36.2, 36.5, 39.1, 40.5, 44.7, 48.8, 54.3, 56.3, 66.5, 213.7 (CO); IR ν_(max) 3435, 2921, 1704, 1005 cm⁻¹. Anal. (C₂₂H₃₄O₂) C, H.

(3α,5α)-13,24-Cyclo-18,21-dinorchola-20(22),23-diene-3,20-diol, 3,20-diacetate (23a)

A mixture of compound 11a (200 mg, 0.61 mmol), NaI (366 mg, 2.44 mmol) and Ac₂O (9 mL) was cooled to 0° C. under N₂ and Me₃SiCl (0.31 mL, 2.44 mmol) was added dropwise. The reaction mixture was stirred at ambient temperature for 24 h and then poured into 10% NaHCO₃ (50 mL). After the mixture was stirred for 10 min, the product was extracted using hexanes (4×50 mL). The combined extracts were washed with 10% NaHCO₃ (5 mL), 10% Na₂S₂O₃ (2×10 mL), water, and dried over Na₂SO₄. The solvent was removed under reduced pressure and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 30:1) to give compound 23a (173 mg, 69%).

Compound 23a was obtained as white crystals: mp 135-136° C. (hexanes); ¹H NMR δ 0.82 (s, 3H, 19-CH₃), 2.06 (s, 3H, CHOC(O)CH₃), 2.15 (s, 3H, ═COC(O)CH₃), 5.02 (m, 1H, CHOAc), 5.56 (d, J=5.7 Hz, 1H, CH═COAc), 5.65 (d, J=9.6 Hz, 1H, CH═CHCH═), 5.84 (dd, J=5.7 Hz, J=9.6 Hz, 1H, CH═CHCH═); ¹³C NMR δ 11.4, 20.1, 21.2, 21.5, 26.1, 28.4, 29.7, 32.3 (2×C), 32.9, 33.0, 35.9, 36.0, 37.5, 40.1, 47.9, 48.4, 54.2, 56.2, 70.1, 107.9 (CH═COAc), 122.4 (═CHCH═COAc), 127.7 (CCH═CH), 154.6 (═COAc), 169.1 (OC(O)CH₃), 170.7 (OC(O)CH₃); IR ν_(max) 3039, 2932, 1763, 1734, 1204. Anal. (C₂₆H₃₆O₄) C, H.

(3α,5α,20R)-13,24-Cyclo-18,21-dinorchol-23-en-3,20-diol, 3-acetate (24a) and (3α,5α,20S)-13,24-Cyclo-18,21-dinorchol-23-en-3,20-diol, 3-acetate (24b)

Compound 23a (170 mg, 0.41 mmol) was dissolved in EtOH (15 mL), and NaBH₄ (78 mg, 2.05 mmol) was added. The solution was stirred under N₂ for 6 h. Most of the EtOH was removed under reduced pressure and the residue was dissolved in EtOAc (50 mL), washed with 5% HCl (10 mL), aqueous NaHCO₃ (10 mL), brine (10 mL), and dried over Na₂SO₄. The solvent was removed and the residue obtained was filtered through a short column (silica gel; hexanes/EtOAc, 8:1) to give a mixture of compounds 24a and 24b (140 mg, 92%). Analytical samples of compounds 24a and 24b were obtained by column chromatography (silica gel; hexanes/EtOAc, 20:1).

Compound 24a was obtained as white crystals: mp 159-161° C.; ¹H NMR δ 0.81 (s, 3H, 19-CH₃), 2.06 (s, 3H, CH₃C(O)O), 4.10 (m, 1H, CHOH), 5.01 (m, 1H, CHOAc), 5.54 (m, 1H, ═CHCH₂), 5.66 (d, 1H, J=10.5 Hz, CH═CHCH₂); ¹³C NMR δ 11.3, 20.6, 20.7, 21.5, 25.8, 26.0, 28.3, 30.7, 32.2, 32.8, 32.9, 35.3, 35.9, 38.6, 40.0, 47.9, 51.0, 54.5, 55.1, 66.8, 70.0, 124.7 (CH═), 129.6 (CH═), 170.6 (C(O)O); IR ν_(max) 3399, 3023, 2929, 1734, 1245. Anal. (C₂₄H₃₆O₃) C, H.

Compound 24b was obtained as white crystals: mp 168-169° C.; ¹HNMR δ 0.83 (s, 3H, 19-CH₃), 2.06 (s, 3H, CH₃C(O)O), 4.06 (m, 1H, CHOH), 5.02 (m, 1H, CHOAc), 5.65 (m, 1H, CH₂CH═), 5.86 (d, J=10.5 Hz, 1H, CCH═); ¹³C NMR δ 11.3, 20.7, 21.5, 25.8, 26.1 (2×C), 28.3, 30.0, 32.2, 32.8 (2×C), 34.9, 35.9, 39.7, 40.0, 42.8, 50.1, 54.2, 55.7, 68.4, 70.1, 124.0 (CH═), 129.7 (CH═), 170.7 (C(O)O); IR ν_(max) 3442, 3021, 2931, 1735, 1249 cm⁻¹. Anal. (C₂₄H₃₆O₃) C, H.

(3α,5α)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorchol-23-ene (28a)

A mixture of compounds 24a and 24b (150 mg, 0.40 mmol), Ph₃P (195 mg, 0.74 mmol), imidazole (101 mg, 1.48 mmol) and I₂ (150 mg, 0.59 mmol) in toluene (15 mL) was heated at 95° C. for 1.5 h. The toluene was removed under reduced pressure and the residue was purified by column chromatography (silica gel, CH₂Cl₂) to give a mixture of compounds 26a and 26b in quantitative yield. This product mixture was used without further purification or characterization.

The mixture of compounds 26a and 26b, i-PrOH (0.20 mL) and HMPA (0.50 mL) in THF (1 mL) was added to a freshly made SmI₂-THF solution (0.1 M, 10 mL) under Ar. The purple solution was stirred at room temperature for 30 min and quenched with saturated aqueous NH₄Cl (1 mL). The solution was extracted with CH₂Cl₂. The combined CH₂Cl₂ extracts were washed with saturated aqueous NH₄Cl, water, and dried over Na₂SO₄. The solvent was removed under reduced pressure and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 30:1) to give compound 28a contaminated with about 20% of the 20(22),23-diene. The mixture was dissolved in acetone (15 mL) and a 2% solution of 4-phenyl-1,2,4-triazoline-3,5-dione in acetone was added dropwise at 0° C. until the pink color persisted. After all of the diene was reacted with 4-phenyl-1,2,4-triazoline-3,5-dione (monitored by TLC), the solvent was removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 50:1) to give compound 28a (94 mg, 66% from compound 24a and 24b) as a single spot on TLC (silica gel plate). NMR analysis showed that product 28a contained ˜10% of another inseparable and unidentified isomeric olefin product.

Compound 28a was obtained as a white solid: mp 117-119° C.; ¹H NMR δ 0.82 (s, 3H, 19-CH₃), 2.05 (s, 3H, CH₃C(O)O), 5.01 (m, 1H, CHOAc), 5.67 (bs, 2H, CH═CH); ¹³C NMR δ 11.4, 20.5, 20.9, 21.2, 21.5, 24.5, 26.1, 26.1, 28.4, 32.3, 32.9 (2×C), 35.0, 35.9, 38.5, 40.1, 43.3, 43.8, 54.5, 55.1, 70.1, 128.0 (CH═), 129.7 (CH═), 170.7 (C(O)O); IR ν_(max) 3019, 2932, 1736, 1446 cm⁻¹. Anal. (C₂₄H₃₆O₂) C, H.

(3α,5α)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorchol-23-en-22-one (29a)

A solution of CrO₃ (280 mg, 2.8 mmol) in CH₂Cl₂ (4 mL) was cooled to −15° C. and 3,5-dimethylpyrazole (274 mg, 2.85 mmol) was added in one portion. The resultant brown slurry was stirred for 30 min followed by addition of compound 28a (40 mg, 0.112 mmol) in CH₂Cl₂ (4 mL). The mixture was stirred at −15° C. for 3 h and a 1:1 mixture of hexanes and ethyl acetate (20 mL) was added. The reaction mixture was filtered through a pad of silica gel. Solvent was removed under reduced pressure to give a residue which was purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) to give compound 29a (28 mg, 67%). This product was contaminated with ˜5% of an unidentified impurity which was removed after hydrolysis of the acetate group.

Partially purified compound 29a was obtained as white solid: mp 133-138° C.; ¹H NMR δ 0.86 (s, 3H, 19-CH₃), 2.07 (s, 3H, CH₃C(O)O), 2.41 (dm, J=17.4 Hz, 1H, CH₂CO), 2.62 (dd, J=4.5 Hz, J=17.4 Hz, 1H, CH₂CO), 5.03 (m, 1H, CHOAc), 6.01 (d, J=10.5 Hz, 1H, ═CHCO), 6.97 (dd, J=1.5 Hz, J=10.5 Hz, 1H, CH═CHCO); ¹³C NMR δ 11.4, 20.7, 21.5, 26.0, 26.7, 27.5, 28.1, 32.0, 32.8, 32.9, 35.3, 35.9, 36.4, 38.2, 40.0, 43.9, 45.5, 54.2, 56.9, 69.9, 130.1 (═CHCO), 152.3 (CH═CHCO), 170.6 (C(O)O), 199.7 (CO).

(3α,5α)-3-Hydroxy-13,24-Cyclo-18,21-dinorchol-23-en-22-one (30a)

Compound 29a (30 mg, 0.08 mmol) was dissolved in MeOH (2 mL) and 15% aq. NaOH (0.2 mL) was added. The solution was refluxed for 20 min and cooled to room temperature. EtOAc (20 mL) was added and the organic layer was washed with water and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue which was purified by column chromatography (silica gel; CH₂Cl₂/EtOAc, 20:1) to give compound 30a (22 mg, 83%).

Compound 30a was obtained as white crystals: mp 168-170° C. (Et₂O-EtOAc); ¹H NMR δ 0.84 (s, 3H, 19-CH₃), 2.41 (dm, J=17.1 Hz, 1H, CH₂CO), 2.62 (dd, J=4.5 Hz, J=17.1 Hz, 1H, CH₂CO), 4.07 (m, 1H, CHOH), 6.00 (d, J=10.2 Hz, 1H, ═CHCO), 6.97 (dd, J=1.8 Hz, J=10.2 Hz, 1H, CH═CHCO); ¹³C NMR δ 11.3, 20.7, 26.7, 27.6, 28.4, 29.0, 32.1, 32.2, 35.4, 35.8, 36.2, 36.5, 38.2, 39.1, 43.9, 45.6, 54.3, 56.9, 66.4, 130.1 (═CHCO), 152.5 (CH═CHCO), 199.9 (CO); IR ν_(max) 3320, 3028, 2926, 1679, 1445. Anal. (C₂₂H₃₂O₂) C, H.

(3α,5α,23R,24R)-23,24-Epoxy-13,24-cyclo-18,21-dinorcholan-3-ol, acetate (31a)

A mixture of NaHCO₃ (33 mg, 0.40 mmol), m-CPBA (103 mg, 0.60 mmol) and compound 28a (71 mg, 0.20 mmol) in CH₂Cl₂ (15 mL) was stirred at room temperature for 5 hrs. It was washed successively with 5% Na₂S₂O₃, 10% NaHCO₃ and brine, and dried over Na₂SO₄. After solvent removal under reduced pressure, the residue obtained was purified by column chromatography (silica gel; hexanes/EtOAc, 50:1) to give compound 31a (67 mg, 90%).

Compound 31a was obtained as a white solid: mp 126-128° C. [containing ˜10% (23S,24R)-epoxide]; ¹H NMR δ 0.81 (s, 3H, 19-CH₃), 2.06 (s, 3H, CH₃C(O)O), 2.96 (d, J=3.9 Hz, 1H, epoxide 24-H), 3.16 (m, 1H, epoxide 23-H), 5.02 (m, 1H, CHOAc); ¹³C NMR δ 11.4, 18.3, 19.4, 21.1, 21.5, 24.5, 26.0, 26.1, 28.3, 32.3, 32.8, 32.9, 34.5, 34.7, 35.9, 40.0, 40.7, 41.3, 54.3, 54.4, 54.6, 55.8, 70.0, 170.6 (C(O)O); IR ν_(max) 2930, 1735, 1235 cm⁻¹.

(3α,5α,23S,24R)-23-Bromo-13,24-cyclo-18,21-dinorcholan-3,24-diol, 3-acetate (32a)

Compound 31a (71 mg, 0.19 mmol) in MeCN (10 mL) was cooled to −40° C. and hydrobromic acid (48%, 0.25 mL) was added dropwise. The solution was stirred at 0° C. for 2 h and then at room temperature for 1 h. EtOAc (50 mL) was added and the organic layer was washed with water to neutral pH, and dried over Na₂SO₄. The solvent was removed under reduced pressure and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 50:1) to give compound 32a (60 mg, 70%).

Compound 32a was obtained as a white solid: mp 161.5-163.5° C.; ¹H NMR δ 0.77 (s, 3H, 19-CH₃), 2.05 (s, 3H, CH₃C(O)O), 3.65 (dd, J=1.8 Hz, J=10.5 Hz, 1H, CHOH), 4.32 (m, 1H, CHBr), 5.00 (m, 1H, CHOAc); ¹³C NMR δ 11.2, 21.6, 22.6, 23.3, 24.8, 24.9, 26.1, 28.4, 31.9, 32.5, 32.9 (2×C), 33.0, 35.3, 36.1, 40.3, 47.7, 48.2, 54.6, 58.3, 63.7, 70.3, 74.4, 170.7 (C(O)O); IR ν_(max) 3554, 2931, 1733, 1261 cm⁻¹. Anal. (C₂₄H₃₇BrO₃) C, H.

(3α,5α,23S)-3-(Acetyloxy)-23-bromo-13,24-cyclo-18,21-dinorcholan-24-one (33a)

Jones reagent was added dropwise to a solution of compound 32a (58 mg, 0.13 mmol) in acetone (15 mL) at 5° C. until an orange color persisted. The resultant mixture was stirred at 0-5° C. for 1 h. 2-propanol was added to consume excess oxidant and the acetone was removed under reduced pressure. The residue obtained was dissolved in EtOAc (30 mL) and washed with water to neutral pH, and dried over Na₂SO₄. The solvent was removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 20:1) to give compound 33a (57 mg, 98%).

Compound 33a was obtained as a white solid: mp 207-209° C.; ¹H NMR δ 0.76 (s, 3H, 19-CH₃), 2.04 (s, 3H, CH₃C(O)O), 4.92 (dd, J=6.0 Hz, J=12.9 Hz, 1H, CHBr), 5.00 (m, 1H, CHOAc); ¹³C NMR δ 11.5, 21.5, 21.6, 23.6, 25.2, 25.4, 26.0, 28.2, 32.3, 32.8, 32.9, 35.2 (2×C), 35.8, 36.3, 40.0, 49.3, 54.6, 56.3, 57.0, 59.8, 70.0, 170.6 (C(O)O), 205.0 (CO); IR ν_(max) 2942, 1733, 1240 cm⁻¹. Anal. (C₂₄H₃₅BrO₃) C, H.

(3α,5α)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorchol-22-en-24-one (34a)

A mixture of compound 33a (54 mg, 0.12 mmol), Li₂CO₃ (89 mg, 1.2 mmol) and LiBr (42 mg, 0.48 mmol) in DMF was heated at 125° C. under N₂ for 24 h. After cooling to room temperature, EtOAc (30 mL) was added and the organic layer was washed with water until neutral pH, and dried over Na₂SO₄. The solvent was removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 45:1) to give compound 34a (31 mg, 70%).

Compound 34a was obtained as white crystals: mp 122-124° C.; ¹H NMR δ 0.87 (s, 3H, 19-CH₃), 2.05 (s, 3H, CH₃C(O)O), 5.02 (m, 1H, CHOAc), 5.80 (m, 1H, ═CHCO), 6.62 (m, 1H, ═CHCH₂); ¹³C NMR δ 11.5, 20.3, 21.5, 24.3, 26.1, 26.7, 27.7, 28.3, 32.7 (2×C), 32.9, 33.1, 35.4, 36.0, 40.3, 45.1, 53.5, 54.3, 57.2, 70.2, 129.4 (═CHCO), 144.4 (═CHCH₂), 170.6 (C(O)O), 204.0 (CO); IR ν_(max) 3031, 2938, 1734, 1666, 1247 cm⁻¹. Anal. (C₂₄H₃₄O₃) C, H.

(3α,5α)-3-Hydroxy-13,24-cyclo-18,21-dinorchol-22-en-24-one (35a)

Using the same procedure described for the preparation of compound 30a from compound 29a, compound 35a (21 mg, 80%) was prepared from compound 34a (30 mg, 0.08 mmol).

Compound 35a was obtained as white crystals: mp 242-243° C.; ¹H NMR δ 0.86 (s, 3H, 19-CH₃), 4.05 (m, 1H, CHOH), 5.80 (m, 1H, ═CHCO), 6.62 (m, 1H, ═CHCH₂); ¹³C NMR δ 11.3, 20.3, 24.3, 26.8, 27.7, 28.5, 29.1, 32.4, 32.8 (2×C), 35.5, 36.0, 36.3, 39.4, 45.1, 53.5, 54.4, 57.2, 66.6, 129.4 (═CHCO), 144.5 (═CHCH₂), 204.1 (CO); IR ν_(max) 3439, 3031, 2908, 1647 cm⁻¹. Anal. (C₂₂H₃₂O₂) C, H.

(3α,5α)-3-Hydroxy-13,24-cyclo-18,21-dinorcholan-24-one (5a)

Using the same procedure described for the preparation of compound 2a from compound 11a, compound 5a (37 mg, 92%) was prepared from compound 35a (40 mg, 0.12 mmol).

Compound 5a was obtained as white crystals: mp 203-204° C. (Et₂O-hexanes); ¹H NMR δ 0.75 (s, 3H, 19-CH₃), 4.04 (m, 1H, CHOH); ¹³C NMR δ 11.3, 21.6, 23.9, 23.9, 24.0, 25.4, 28.5, 29.0, 32.3, 32.6, 35.1, 35.3, 35.9, 36.2, 39.3, 40.2, 49.7, 54.9, 56.4, 58.5, 66.6, 216.7 (CO); IR ν_(max) 3317, 2923, 1708, 1003 cm⁻¹. Anal. (C₂₂H₃₄O₂) C, H.

(3α,5α)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorcholan-20-one (36)

Compound 2a (100 mg, 0.303 mmol) was dissolved in pyridine (1 mL), and Ac₂O (0.3 mL) was added. The mixture was stirred at room temperature for 20 h and then poured into saturated aqueous NaHCO₃ (10 mL). After stirring at room temperature for 10 min, the product was extracted with EtOAc. The combined EtOAc extracts were washed with 3% HCl, 5% NaHCO₃ and water and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue which was purified by column chromatography (silica gel; hexanes/EtOAc, 50:1) to give compound 36 (105 mg, 94%).

Compound 36 was obtained as white crystals: mp 197-198° C. (hexanes); IR ν_(max) 2938, 1732, 1696, 1244 cm⁻¹; ¹H NMR δ 0.80 (s, 3H), 2.05 (s, 3H), 2.50 (m, 1H), 5.01 (m, 1H); ¹³C NMR δ 11.4, 20.4, 21.5, 22.2 (2×C), 25.1, 26.1, 27.0, 28.2, 32.1, 32.8 (2×C), 33.5, 35.2, 35.9, 37.4, 40.0, 49.6, 53.9, 56.8, 61.6, 70.0, 170.7, 215.5.

(3α,5α,20R)-3-Hydroxy-13,24-cyclo-18,21-dinorcholane-20-carbonitrile (39) and (3α,5α,20S)-3-Hydroxy-13,24-cyclo-18,21-dinorcholane-20-carbonitrile (40)

To the solution of compound 36 (53 mg, 0.142 mmol) in anhydrous THF (8 mL) was added diethyl cyanophosphonate (100 mg, 0.570 mmol) and LiCN (0.5 M solution in DMF, 1.14 mL, 0.57 mmol). The mixture was stirred at room temperature for 3 h and the solvent was removed under reduced pressure. The residue obtained was then purified by column chromatography (silica gel; hexanes/EtOAc, 4:1) to give compound 37 as a colorless oil that was used without further separation.

The mixture of compound 37 and MeOH (0.12 mL) in THF (3 mL) was added to a freshly made SmI₂-THF solution (0.1 M, 20 mL) under Ar. The resultant dark blue solution was stirred at room temperature overnight and then cooled to 0° C. 3% HCl (5 mL) was added to quench the reaction. Solvent was removed under reduced pressure and the residue was dissolved in EtOAc and washed with 5% NaHCO₃, 5% Na₂S₂O₃ and brine and dried over Na₂SO₄. After solvent removal under reduced pressure, compound 38 was obtained and it was dissolved in MeOH (8 mL). Then, 2.5 N NaOH (1.2 mL) was added. The solution obtained was stirred at room temperature overnight and MeOH was removed under reduced pressure. The residue was dissolved in CH₂Cl₂ and washed with water, 3% HCl and water and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue which was purified by column chromatography (silica gel; dichloroethane) to give compound 39 (25 mg, 51% from 36) and compound 40 (22 mg, 45% from 36).

Compound 39 was obtained as white crystals: mp 213-214° C. (EtOAc-hexanes); IR ν_(max) 3409, 2929, 2232, 1443, 1001 cm⁻¹; ¹H NMR δ 0.76 (s, 3H), 2.75 (m, 1H), 4.04 (m, 1H); ¹³C NMR δ 11.2, 20.0, 20.3, 21.7, 22.9, 23.5, 24.8, 27.3, 28.4, 29.0, 31.9, 32.2, 32.8, 34.6, 35.9, 36.2, 39.1, 41.7, 46.8, 54.3, 56.8, 66.5, 122.5.

Compound 40 was obtained as white crystals: mp 250-251° C. (EtOAc-hexanes); IR ν_(max) 3319, 2922, 2234, 1448, 1009 cm⁻¹; ¹H NMR δ 0.77 (s, 3H), 2.42 (m, 1H), 2.76 (m, 1H), 4.04 (m, 1H); ¹³C NMR δ 11.2, 17.9, 20.2, 22.5, 23.6, 23.8, 25.9, 27.1, 28.4, 29.0, 32.0, 32.1, 34.1, 34.5, 35.8, 36.2, 39.1, 41.5, 46.9, 54.3, 57.1, 66.5, 123.3.

(3α,5α)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorcholan-22-one (41)

Using the same procedure described for the preparation of compound 36, compound 41 (60 mg, 97%) was prepared from compound 3a (55 mg, 0.167 mmol).

Compound 41 was obtained as white crystals: mp 178-180° C. (hexanes); IR ν_(max) 2936, 1733, 1237 cm⁻¹; ¹H NMR δ 0.80 (s, 3H), 2.06 (s, 3H), 2.39 (dt, J=5.7, 14.4 Hz, 1H), 2.54 (dd, J=5.7, 14.4 Hz, 1H), 5.02 (m, 1H); ¹³C NMR δ 11.4, 20.4, 21.5, 23.4, 23.7, 26.1, 27.7, 28.2, 32.0, 32.7, 32.9, 32.9, 35.6, 35.9, 37.0, 40.1, 41.3, 41.6, 49.0, 54.3, 55.6, 70.0, 170.6, 213.3.

(3α,5α,22S)-3-Hydroxy-13,24-cyclo-18,21-dinorcholane-22-carbonitrile (44) and (3α,5α,22R)-3-Hydroxy-13,24-cyclo-18,21-dinorcholane-22-carbonitrile (45)

Using the same procedure described for the preparation of compound 39 and 40, compound 44 (14 mg, 26% from 41) and compound 45 (36 mg, 68% from 41) were prepared from compound 41 (58 mg, 0.156 mmol). Compounds 44 and 45 were separated by HPLC (silica gel, hexanes/EtOAc, 25:1, 2 mL/min).

Compound 44 was obtained as white crystals: mp 199-200° C. (Et₂O-hexanes); IR ν_(max) 3345, 2926, 2238, 1444, 1003 cm⁻¹; ¹H NMR δ 0.76 (s, 3H), 2.02 (m, 1H), 2.58 (m, 1H), 4.04 (m, 1H); ¹³C NMR δ 11.2, 20.1, 21.9, 23.8, 24.0, 25.0, 25.2, 28.4 (2×C), 29.0, 32.0, 32.2, 32.9, 34.7, 35.9, 36.2, 39.2, 40.5, 44.7, 54.4, 56.7, 66.5, 123.3.

Compound 45 was obtained as white crystals: mp 244-246° C. (CH₂Cl₂-EtOAc-hexanes); IR ν_(max) 3513, 2929, 2234, 1456, 1016 cm⁻¹; ¹H NMR δ 0.78 (s, 3H), 2.20 (m, 1H), 2.85 (m, 1H), 4.05 (m, 1H); ¹³C NMR δ 11.2, 19.1, 20.1, 23.4, 23.6, 23.9, 25.8, 25.9, 28.5, 29.0, 32.0, 32.2, 33.1, 34.6, 35.9, 36.2, 39.2, 41.1, 44.5, 54.5, 56.9, 66.5, 124.2.

(3α,5α)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorcholan-23-one (46)

Using the same procedure described for the preparation of compound 36, compound 46 (59 mg, 95%) was prepared from compound 4a (55 mg, 0.167 mmol).

Compound 46 was obtained as white crystals: mp 183-185° C. (hexanes); IR ν_(max) 2931, 1734, 1712, 1247, 1235 cm⁻¹; ¹H NMR δ 0.78 (s, 3H), 2.05 (s, 3H), 2.50 (m, 1H), 5.01 (m, 1H); ¹³C NMR δ 11.4, 19.8, 21.5, 24.3, 24.9, 25.2, 26.0, 28.1, 31.8, 32.8, 32.8, 34.2, 34.8, 35.9, 36.4, 40.0, 40.5, 44.7, 48.7, 54.2, 56.3, 70.0, 170.5, 213.5.

(3α,5α,20R)-3-Hydroxy-13,24-cyclo-18,21-dinorcholane-23-carbonitrile (49) and (3α,5α,20S)-3-Hydroxy-13,24-cyclo-18,21-dinorcholane-23-carbonitrile (50)

Using the same procedure described for the preparation of compounds 39 and 40, compound 49 (27 mg, 53% from 46) and compound 50 (15 mg, 29% from 46) were prepared from compound 46 (56 mg, 0.150 mmol). Compounds 49 and 50 were separated by HPLC (silica gel, hexanes/EtOAc, 6:1, 2 mL/min).

Compound 49 was obtained as white crystals: mp 182-183° C. (EtOAc-hexanes); IR ν_(max) 3343, 2929, 2232, 1451, 1003 cm⁻¹; ¹H NMR δ 0.79 (s, 3H), 2.66 (m, 1H), 2.88 (m, 1H), 4.05 (m, 1H); ¹³C NMR δ 11.2, 20.1, 20.9, 22.9, 23.7, 24.0, 24.0, 24.7, 28.5, 29.1, 32.1, 32.1, 34.2, 34.6, 35.8, 36.2, 39.2, 41.0, 44.7, 54.5, 58.1, 66.5, 123.8.

Compound 50 was obtained as white crystals: mp 157-159° C. (Et₂O-hexanes); IR ν_(max) 3401, 2927, 2239, 1446, 1003 cm⁻¹; ¹H NMR δ 0.79 (s, 3H), 2.43 (m, 1H), 4.05 (m, 1H); ¹³C NMR δ 11.3, 20.1, 23.4, 23.8, 24.3, 24.7, 24.8, 27.1, 28.4, 29.0, 32.0, 32.2, 33.1, 34.6, 35.9, 36.2, 39.2, 41.4, 44.3, 54.5, 57.0, 66.5, 123.5.

(3α,5α)-20-Methylene-13,24-cyclo-18,21-dinorcholan-3-ol (51)

A suspension of NaH (60% in mineral oil, 75 mg, 1.88 mmol) in anhydrous DMSO (3 mL) was heated at 75° C. for 45 min and cooled to room temperature. Methyltriphenylphosphonium bromide (690 mg, 1.93 mmol) in DMSO (2 mL) was added and stirred at room temperature for 10 min. Compound 2a (127 mg, 0.385 mmol) in DMSO (1.5 mL) was then added. The mixture obtained was heated at 70° C. for 4 h and cooled to room temperature. Brine was added and the product was extracted with EtOAc. The combined EtOAc extracts were washed with water and brine and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue which was purified by column chromatography (silica gel; hexanes/EtOAc, 5:1) to give compound 51 (116 mg, 92%).

Compound 51 was obtained as a white solid: mp 211-213° C. (EtOAc-hexanes); IR ν_(max) 3295, 2927, 1645, 1436, 1001 cm⁻¹; ¹H NMR δ 0.77 (s, 3H), 4.04 (m, 1H), 4.61 (m, 2H); ¹³C NMR δ 11.2, 20.4, 22.6, 23.2, 24.7, 27.4, 28.6, 29.1, 30.9, 32.3 (2×C), 33.3, 35.0, 35.9, 36.2, 39.2, 44.9, 54.5, 55.9, 56.9, 66.6, 107.8, 150.2.

(3α,5β)-20-Methylene-13,24-cyclo-18,21-dinorcholan-3-ol (52)

Using the same procedure described for the preparation of compound 51, compound 52 (41 mg, 82%) was prepared from compound 2b (50 mg, 0.152 mmol).

Compound 52 was obtained as a white solid: mp 131-133° C. (hexanes); IR ν_(max) 3299, 2927, 1645, 1451, 1040 cm⁻¹; ¹H NMR δ 0.91 (s, 3H), 3.63 (m, 1H), 4.61 (m, 2H); ¹³C NMR δ 20.4, 22.5, 23.1, 23.4, 24.7, 26.7, 27.1, 27.5, 30.5, 30.9, 33.4, 34.7, 35.3, 35.4, 36.4, 40.6, 42.1, 44.9, 55.9, 56.9, 71.8, 107.8, 150.1.

(3α,5α)-22-Methylene-13,24-cyclo-18,21-dinorcholan-3-ol (53)

Using the same procedure described for the preparation of compound 51, compound 53 (17 mg, 43%) was prepared from compound 3a (40 mg, 0.121 mmol).

Compound 53 was obtained as a white solid: mp 187-188° C. (hexanes); IR ν_(max) 3312, 2926, 1450 cm⁻¹; ¹H NMR δ 0.77 (s, 3H), 4.04 (m, 1H), 4.58 (s, 1H), 4.69 (s, 1H); ¹³C NMR δ 11.2, 20.3, 23.9, 24.4, 25.5, 28.5, 29.1, 30.5, 32.2, 32.2, 33.0, 34.3, 34.9, 35.9, 36.2, 39.3, 41.3, 47.7, 54.6, 56.8, 66.6, 108.3, 147.9.

(3α,5α)-3-Methoxymethoxy-13,24-cyclo-18,21-dinorcholan-20-one (54)

Chloromethyl methyl ether (84 mg, 1.05 mmol) was added to a solution of compound 2a (115 mg, 0.35 mmol) and N,N-diisopropyl ethylamine (0.30 mL, 1.75 mmol) in CH₂Cl₂ (10 mL). The resultant solution was stirred at room temperature for 20 h. The solvent was partially removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 15:1) to give compound 54 (126 mg, 97%).

Compound 54 was obtained as white crystals: mp 138-139° C. (Hexanes); IR ν_(max) 2928, 1702, 1446, 1045 cm⁻¹; ¹H NMR δ 0.79 (s, 3H), 2.50 (m, 1H), 3.36 (s, 3H), 3.83 (m, 1H), 4.65 (m, 2H); ¹³C NMR δ 11.3, 20.3, 22.1 (2×C), 25.0, 26.2, 26.9, 28.4, 32.1, 32.7, 33.5, 33.5, 35.1, 35.8, 37.3, 39.6, 49.5, 53.9, 55.0, 56.7, 61.4, 71.5, 94.5, 215.3.

(3α,5α)-3-Methoxymethoxy-13,24-cyclo-18,21-dinorchol-20(22)-en-20-ol trifluoromethanesulfonate (55)

A solution of compound 54 (128 mg, 0.342 mmol) and N-phenyltrifluoromethanesulfonimide (367 mg, 1.03 mmol) in anhydrous THF (20 mL) was cooled to −78° C. and KHMDS (0.5 M solution in toluene, 1.37 mL, 0.685 mmol) was added. The mixture was stirred at room temperature for 1 h and saturated aqueous NH₄Cl (1 mL) was added. The product was extracted with ether and the combined ether extracts were washed with aqueous NH₄Cl and brine and dried over Na₂SO₄. The solvent was removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 50:1) to give compound 55 (169 mg, 97%). Compound 55 was partially characterized. It had ¹H NMR δ 0.79 (s, 3H), 3.37 (s, 3H), 3.83 (m, 1H), 4.66 (m, 2H), 5.61 (m, 1H).

(3α,5α)-3-Methoxymethoxy-13,24-cyclo-18,21-dinorchol-20(22)-ene-20-carbonitrile (56)

A mixture of compound 55 (165 mg, 0.333 mmol), triethylamine (3 mL), trimethylsilyl cyanide (0.5 mL) and tetrakis(triphenylphosphine)palladium(0) (96.3 mg, 0.083 mmol) in benzene (10 mL) was refluxed under N₂ for 20 h. The solvent was partially removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 30:1) to give compound 56 (45 mg, 35%).

Compound 56 was obtained as white crystals: mp 136-138° C. (hexanes); IR ν_(max) 2927, 2212, 1456, 1041 cm⁻¹; ¹H NMR δ 0.79 (s, 3H), 3.37 (s, 3H), 3.83 (m, 1H), 4.66 (m, 2H), 6.50 (t, 1H, J=3.6 Hz); ¹³C NMR δ 11.4, 18.5, 19.9, 22.6, 24.4, 26.3, 28.5, 29.6, 32.0, 32.8, 32.8, 33.6, 34.8, 35.9, 39.7, 41.1, 47.4, 54.3, 55.1, 55.5, 71.5, 94.5, 116.5, 119.9, 142.6.

(3α,5α)-3-Hydroxy-13,24-cyclo-18,21-dinorchol-20(22)-ene-20-carbonitrile (57)

12 N HCl (0.6 mL) was added to a solution of compound 56 (41 mg, 0.106 mmol) in MeOH (3 mL) and CH₂Cl₂ (0.5 mL) and stirred at room temperature for 2 h. EtOAc (20 mL) was added and the organic phase was washed with water, 5% NaHCO₃ and brine and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue which was purified by column chromatography (silica gel; hexanes/EtOAc, 8:1) to give compound 57 (32 mg, 89%).

Compound 57 was obtained as white crystals: mp 193-195° C. (EtOAc-hexanes); IR ν_(max) 3426, 2925, 2212, 1455, 1002 cm⁻¹; ¹H NMR δ 0.79 (s, 3H), 4.04 (m, 1H), 6.50 (t, 1H, J=3.6 Hz); ¹³C NMR δ 11.2, 18.5, 19.9, 22.6, 24.4, 28.4, 29.0, 29.6, 32.0, 32.2, 32.7, 34.8, 35.8, 36.2, 39.1, 41.1, 47.4, 54.3, 55.5, 66.4, 116.4, 119.9, 142.6.

(3α,5α)-13,24-Cyclo-18,21-dinorchol-20(22),23-dien-3-ol acetate (59)

Mesyl chloride (20 μL, 0.258 mmol) was added to a solution of compound 24a (24 mg, 0.065 mmol) and triethylamine (80 μL, 0.581 mmol) in CH₂Cl₂ (5 mL) at 0° C. and stirred at room temperature for 1 h. The reaction mixture was washed with water and 3% HCl and water and dried over Na₂SO₄. The solvent was removed under reduced pressure to give crude mesylate 58. It was dissolved in toluene (2 mL) and DBU (0.1 mL) was added. The mixture was refluxed for 5 h and cooled to room temperature. The reaction mixture was washed with 3% HCl and water and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue which was purified by column chromatography (silica gel; hexanes/EtOAc, 20:1) to give compound 59 (19 mg, 83% from 24a).

Compound 59 was obtained as a colorless oil; IR ν_(max) 3032, 2932, 1736, 1445, 1246 cm⁻¹; ¹H NMR δ 0.83 (s, 3H), 2.06 (s, 3H), 5.02 (m, 1H), 5.73-5.80 (m, 2H), 5.88 (m, 1H), 5.95 (m, 1H); ¹³C NMR δ 11.4, 20.1, 21.5, 26.1, 28.4, 30.1, 32.4, 32.9, 33.0, 33.2, 35.7, 35.9, 37.4, 40.1, 44.5, 44.9, 54.3, 56.3, 70.1, 121.4, 124.1, 130.0, 131.1, 170.7.

(3α,5α)-13,24-Cyclo-18,21-dinorchol-20(22),23-dien-3-ol (60)

LiAlH₄ (10 mg, 0.263 mmol) was added to a solution of compound 59 (20 mg, 0.056 mmol) in anhydrous THF (5 mL) and stirred at room temperature for 20 min. The reaction mixture was cooled to 0° C. and water (0.1 mL) was added dropwise to quench the reaction. The precipitate that formed was filtered through a pad of Celite 545. The solvent was removed from the filtrate and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) to give compound 60 (16 mg, 91%).

Compound 60 was obtained as a white solid: mp 136-138° C. (Hexanes); IR ν_(max) 3318, 3034, 2928, 1445, 1004 cm⁻¹; ¹H NMR δ 0.82 (s, 3H), 4.05 (m, 1H), 5.74-5.80 (m, 2H), 5.88 (m, 1H), 5.95 (m, 1H); ¹³C NMR δ 11.2, 20.1, 28.6, 29.1, 30.1, 32.3, 32.5, 33.2, 35.7, 35.9, 36.2, 37.5, 39.2, 44.5, 44.9, 54.4, 56.3, 66.6, 121.3, 124.0, 130.1, 131.2.

(3α,5α)-13,24-Cyclo-18,21-dinorchol-23-en-3-ol (61)

Using the same procedure described for the preparation of compound 60, compound 61 (45 mg, 85%) was prepared from compound 28a (60 mg, 0.169 mmol).

Compound 61 was obtained as a white solid: mp 166.5-169° C. (hexanes); ¹H NMR δ 0.81 (s, 3H), 4.04 (m, 1H), 5.68 (bs, 2H); ¹³C NMR δ 11.2, 20.5, 20.9, 21.3, 24.6, 26.2, 28.6, 29.1, 32.2, 32.4, 35.1, 35.9, 36.3, 38.5, 39.2, 43.4, 43.8, 54.7, 55.2, 66.6, 127.9, 129.8.

(3α,5α,20E)-3-Methoxymethoxy-13,24-cyclo-18-norcholan-20-ene-21-carbonitrile (62)

Compound 54 (50 mg, 0.134 mmol) and (triphenylphosphoranylidene)acetonitrile (100 mg, 0.332 mmol) was heated at 160° C. under N₂ for 15 h and then purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) to give compound 62 (37 mg, 70%).

Compound 62 was obtained as white crystals: mp 159-161° C. (hexanes); IR ν_(max) 2928, 2215, 1625, 1446, 1041 cm⁻¹; ¹H NMR δ 0.77 (s, 3H), 2.07 (t, 1H, J=9.0 Hz), 2.22 (m, 1H), 2.76 (m, 1H), 3.37 (s, 3H), 3.83 (m, 1H), 4.66 (m, 1H), 5.03 (d, 1H, J=1.8 Hz); ¹³C NMR δ 11.4, 20.3, 22.4, 22.7, 24.7, 26.3, 28.0, 28.5, 29.0, 32.1, 32.8, 33.2, 33.6, 35.1, 35.9, 40.0, 47.4, 54.2, 55.1, 56.4, 57.0, 71.6, 92.5, 94.5, 117.2, 170.1.

(3α,5α,20E)-3-Hydroxy-13,24-cyclo-18-norcholan-20-ene-21-carbonitrile (63)

Using the same procedure described for the preparation of compound 57, compound 63 (34 mg, 94%) was prepared from compound 62 (41 mg, 0.103 mmol).

Compound 63 was obtained as white crystals: mp 210-212° C. (ether-hexanes); IR ν_(max) 3308, 2928, 2217, 1444 cm⁻¹; ¹H NMR δ 0.77 (s, 3H), 2.07 (t, 1H, J=9.0 Hz), 2.22 (m, 1H), 2.77 (m, 1H), 4.04 (m, 1H), 5.04 (d, 1H, J=1.5 Hz); ¹³C NMR δ 11.2, 20.3, 22.4, 22.7, 24.7, 28.0, 28.4, 28.9, 29.0, 32.2 (2×C), 33.2, 35.0, 35.8, 36.1, 39.1, 47.4, 54.2, 56.4, 56.9, 66.5, 92.5, 117.2, 170.0.

(3α,5α,20E)-3-Hydroxy-13,24-cyclo-18-norcholan-20-ene-21-carbonitrile (63) and (3α,5α,20Z)-3-Hydroxy-13,24-cyclo-18-norcholan-20-ene-21-carbonitrile (64)

Diethyl cyanomethylphosphonate (0.78 mL, 4.83 mmol) was added dropwise to the mixture of NaH (60% in mineral oil, 175 mg, 4.38 mmol) and THF (10 mL) at room temperature and refluxed for 10 min. Compound 2a (280 mg, 0.85 mmol) in THF (20 mL) was then added and reflux was continued for 20 min. The reaction mixture was then cooled to room temperature. EtOAc (100 mL) was added and the organic phase was washed with water and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue that was purified by column chromatography (silica gel; CH₂Cl₂/EtOAc, 40:1) to give compound 63 (164 mg, 55%) and compound 64 (109 mg, 36%).

Compound 63 was obtained as white crystals: mp. 214-216° C. (EtOAc-hexanes); ¹H NMR δ 0.77 (s, 3H), 2.07 (t, 1H, J=9.0 Hz), 2.22 (m, 1H), 2.77 (dm, 1H, J=15.6 Hz), 4.04 (m, 1H), 5.04 (d, 1H, J=1.5 Hz); ¹³C NMR δ 11.1, 20.2, 22.2, 22.6, 24.6, 27.9, 28.3, 28.9 (2×C), 32.1 (2×C), 33.1, 34.9, 35.7, 36.0, 39.0, 47.3, 54.1, 56.3, 56.8, 66.3, 92.4, 117.2, 170.0; IR ν_(max) 3308, 2928, 2217, 1444 cm⁻¹.

Compound 64 was obtained as white crystals: mp. 201.5-203° C. (ether-hexanes); ¹H NMR δ 0.77 (s, 3H), 2.18 (m, 1H), 2.32 (m, 1H), 2.69 (t, 1H, J=9.3 Hz), 4.04 (m, 1H), 5.05 (d, 1H, J=1.8 Hz); ¹³C NMR δ 11.2, 20.2, 22.3, 23.0, 24.7, 27.3, 28.4, 29.0, 31.8, 32.1, 32.1, 32.9, 35.0, 35.8, 36.1, 39.1, 47.4, 53.0, 54.1, 56.8, 66.4, 92.8, 117.1, 170.1; IR ν_(max) 3401, 2927, 2215, 1621, 1445 cm⁻¹.

(3α,5α,20S)-3-Methoxymethoxy-13,24-cyclo-18,21-dinorcholan-20-ol (65) and (3α,5α,20R)-3-Methoxymethoxy-13,24-cyclo-18,21-dinorcholan-20-ol (66)

The mixture of compound 18a (180 mg, 0.48 mmol) and NaBH₄ (60 mg, 1.58 mmol) in EtOH (10 mL) was stirred at room temperature for 30 min and EtOH was removed under reduced pressure. EtOAc (30 mL) was added and the solution was washed with water, 5% HCl and water and dried over Na₂SO₄. Solvent was removed under reduced pressure and the residue purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) gave compound 65 (55 mg, 30%) and compound 66 (115 mg, 64%).

Compound 65 was obtained as white solid: mp. 131-133° C.; ¹H NMR δ 0.78 (s, 3H), 2.29 (m, 1H), 3.37 (s, 3H), 3.82 (m, 1H), 3.91 (bs, 1H), 4.66 (m, 2H); ¹³C NMR δ 11.4, 15.5, 20.4, 23.0, 24.1, 25.4, 26.3, 28.5, 28.8, 32.0, 32.8, 33.6, 34.4, 35.5, 35.9, 39.7, 41.1, 53.0, 54.4, 55.1, 57.3, 69.7, 71.6, 94.5; IR ν_(max) 3369, 2923, 1445, 1040 cm⁻¹.

Compound 66 was obtained as white solid: mp. 136-138° C.; ¹H NMR δ 0.77 (s, 3H), 1.97 (m, 1H), 3.37 (s, 3H), 3.82 (m, 1H), 3.87 (m, 1H), 4.66 (m, 2H); ¹³C NMR δ 11.4, 20.2, 20.4, 20.6, 22.2, 23.6, 26.3, 28.5, 30.0, 32.1, 32.8, 33.6 (2×C), 34.9, 36.0, 39.8, 44.4, 52.6, 54.6, 55.1, 57.1, 69.7, 71.6, 94.5; IR ν_(max) 3401, 2923, 1446, 1041 cm⁻¹.

(3α,5α,20S)-13,24-cyclo-18,21-dinorcholane-3,20-diol (67)

37% aqueous HCl (0.6 mL) was added the solution of compound 65 (25 mg, 66 μmol) in CH₃OH (2 mL). The solution was stirred at room temperature for 1 h and EtOAc (30 mL) was added. It was washed with water, 10% NaHCO₃, and brine and dried over Na₂SO₄. Solvent was removed under reduced pressure and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 6:1) to give compound 67 (21 mg, 95%).

Compound 67 was obtained as white crystals: mp 261-262° C. (CHCl₃-hexanes); ¹H NMR (CDCl₃/CD₃OD) δ 0.77 (s, 3H), 2.29 (m, 1H), 3.90 (m, 1H), 4.01 (m, 1H); ¹³C NMR δ 11.1, 15.4, 20.3, 22.8, 24.0, 25.3, 28.4, 28.5, 28.6, 32.0, 32.0, 34.3, 35.2, 35.6, 36.0, 39.0, 40.9, 52.6, 54.3, 57.2, 66.2, 69.4; IR ν_(max) 3307, 2916, 1443, 1001 cm⁻¹.

(3α,5α,20R)-13,24-cyclo-18,21-dinorcholane-3,20-diol (68)

Using the same procedure described for the preparation of compound 67 from compound 65, compound 68 (20 mg, 91%) was prepared from compound 66 (25 mg, 66 μmol).

Compound 68 was obtained as white crystals: mp 269-271° C. (methanol); ¹H NMR (CDCl₃/CD₃OD) δ0.78 (s, 3H), 2.00 (m, 1H), 3.85 (m, 1H), 3.98 (m, 1H); ¹³C NMR δ 11.7, 20.9, 21.1 (2×C), 22.8, 24.2, 29.2 (2×C), 29.9, 32.8, 32.9, 34.3, 35.6, 36.2, 36.8, 39.8, 44.9, 53.2, 55.4, 57.8, 66.7, 69.9; IR ν_(max) 3338, 2929, 1444, 1049 cm⁻¹.

(3α,5α,20S)-20-Methoxy-13,24-cyclo-18,21-dinorcholan-3-ol (69)

The solution of compound 65 (30 mg, 80 mmol) in THF (3 mL) was added to the slurry of NaH (60% in mineral oil, 16 mg, 0.40 mmol) in THF (2 mL) and stirred for 10 min. MeI (27 μL, 0.44 mmol) was added and refluxed overnight. The same amount of NaH and MeI was added again and refluxed for another 1 h and cooled to room temperature. Water was added to the reaction mixture and it was extracted with EtOAc. The combined EtOAc extracts were washed with water to neutral pH and then dried over Na₂SO₄. Solvent was removed under reduced pressure and the oil obtained was dissolved in MeOH (3 mL) and 37% HCl (1 mL) was added and stirred at room temperature for 2 h. EtOAc (30 mL) was added and it was washed with water and brine to neutral pH and then dried over Na₂SO₄. Solvent was removed under reduced pressure and the residue purified by column chromatography (silica gel; hexanes/EtOAc, 8:1) gave compound 69 (24 mg, 87%).

Compound 69 was obtained as white crystals: mp 182-183° C. (EtOAc-hexanes); ¹H NMR δ 0.76 (s, 3H), 2.25 (m, 1H), 3.28 (s, 3H), 3.32 (m, 1H), 4.03 (m, 1H); ¹³C NMR δ 11.2, 16.1, 20.2, 23.1, 24.2, 25.4 (2×C), 28.5, 29.0, 32.1 (2×C), 34.5, 34.8, 35.9, 36.2, 39.2, 41.3, 48.6, 54.5, 56.0, 57.4, 66.6, 78.7; IR ν_(max) 3306, 2927, 1446, 1089 cm⁻¹.

(3α,5α,20R)-20-Methoxy-13,24-cyclo-18,21-dinorcholan-3-ol (70)

Using the same procedure described for the preparation of compound 69 from compound 65, compound 70 (29 mg, 90%) was prepared from compound 66 (35 mg, 93 μmol).

Compound 70 was obtained as white crystals: mp 200-202° C. (hexanes); ¹H NMR δ0.77 (s, 3H), 1.97 (m, 1H), 3.31 (s, 3H), 3.39 (m, 1H), 4.04 (m, 1H); ¹³C NMR δ 11.2, 20.2, 20.4, 20.7, 22.5, 23.6, 26.6, 28.5, 29.0, 32.1, 32.2, 33.8, 34.9, 35.9, 36.2, 39.2, 44.1, 49.3, 54.6, 55.4, 57.1, 66.5, 78.5; IR ν_(max) 3293, 2921, 1445, 1103 cm⁻¹.

(3α,5α,20R,22S)-20,22-Epoxy-13,24-cyclo-18,21-dinorcholan-3-ol (71) and (3α,5α,20S,22R)-20,22-epoxy-13,24-cyclo-18,21-dinorcholan-3-ol (72)

The mixture of compound 13a (96 mg, 0.31 mmol), NaHCO₃ (46 mg, 0.55 mmol) and m-CPBA (77% max, 106 mg, 0.47 mmol) in CH₂Cl₂ (15 mL) was stirred at room temperature for 4 h. The solution was washed with water, 5% NaHCO₃, 5% Na₂S₂O₃ and water and dried over Na₂SO₄. Solvent was removed under reduced pressure and the residue purified by column chromatography (silica gel; CH₂Cl₂/EtOAc, 50:1) gave compound 71 (33 mg, 33%) and compound 72 (54 mg, 54%).

Compound 71 was obtained as white crystals: mp 206-208° C. (EtOAc-hexanes); ¹H NMR δ 0.75 (s, 3H), 3.05 (dd, 1H, J=1.5, 3.9 Hz), 3.18 (dd, 1H, J=3.9, 6.3 Hz), 4.03 (m, 1H); ¹³C NMR δ 11.1, 18.8, 20.0, 20.4, 24.3, 24.6, 28.5, 29.0, 32.1 (2×C), 34.3, 34.9, 35.8, 36.1, 39.1, 41.5, 44.7, 52.3, 54.4, 55.9, 56.7, 66.5; IR ν_(max) 3400, 2927, 1435 cm⁻¹.

Compound 72 was obtained as white crystals: mp 203.5-205° C. (acetone-hexanes); ¹H NMR δ 0.77 (s, 3H), 3.13 (m, 1H), 3.22 (m, 1H), 4.03 (m, 1H); ¹³C NMR δ 11.1, 15.5, 19.8, 20.1, 24.3, 25.1, 28.5, 28.9, 32.2 (2×C), 33.8, 34.8, 35.8, 36.2, 39.1, 39.8, 43.8, 53.1, 53.6, 54.4, 55.7, 66.4; IR ν_(max) 3233, 2921, 1432, 1000 cm⁻¹.

(3α,5α,20S)-20,21-Epoxy-13,24-cyclo-18-norcholan-3-ol (73) and (3α,5α,20R)-20,21-Epoxy-13,24-cyclo-18-norcholan-3-ol (74)

Using the same procedure described for the preparation of compound 71 and 72 from compound 13a, compound 73 (30 mg, 48%) and compound 74 (26 mg, 41%) was prepared from compound 51 (60 mg, 0.18 mmol). Compounds 73 and 74 were separated by column chromatography (silica gel; CH₂Cl₂/EtOAc, 30:1).

Compound 73 was obtained as white crystals: mp. 186-192° C. (EtOAc-hexanes, decomposed); ¹H NMR δ 0.78 (s, 3H), 2.00 (m, 1H), 2.25 (m, 1H), 2.48 (d, 1H, J=4.8 Hz), 2.46 (d, 1H, J=4.8 Hz), 4.04 (m, 1H); ¹³C NMR δ 11.2, 19.2, 20.2, 22.2, 24.4, 24.9, 28.5, 29.0, 29.3, 32.1, 32.2, 33.8, 34.7, 35.8, 36.2, 39.1, 43.6, 51.4, 53.4, 54.4, 56.8, 58.9, 66.5; IR ν_(max) 3307, 2927, 1445 cm⁻¹.

Compound 74 was obtained as white crystals: mp. 206-211° C. (EtOAc-hexanes, decomposed); ¹H NMR δ 0.78 (s, 3H), 2.02 (m, 2H), 2.59 (d, 1H, J=5.4 Hz), 2.55 (dd, 1H, J=1.5, 5.4 Hz), 4.05 (m, 1H); ¹³C NMR δ 11.2, 20.2, 21.3, 22.2, 23.6, 24.2, 28.4, 28.9, 29.3, 32.1, 32.2, 33.5, 35.0, 35.9, 36.2, 39.1, 45.7, 53.5, 54.4, 55.7, 56.8, 59.4, 66.5; IR ν_(max) 3306, 2928, 1455 cm⁻¹.

(3α,5α)-3-Methoxymethoxy-21-methyl-13,24-cyclo-18-norchol-20-ene (75)

Ethyltriphenylphosphonium bromide (870 mg, 2.35 mmol) was added to the mixture of KOBu^(t) (240 mg, 2.14 mmol) in THF (12 mL) at room temperature and refluxed for 30 min. Compound 18a (165 mg, 0.44 mmol) in THF (10 mL) was then added and refluxed for another 30 min and cooled to room temperature. Water was added to the reaction mixture and it was extracted with EtOAc. The combined EtOAc extracts were washed with water and dried over Na₂SO₄. Solvent was removed under reduced pressure and the residue purified by column chromatography (silica gel; CH₂Cl₂/EtOAc, 50:1) gave compound 75 (166 mg, 98%) as a colorless oil. It is a mixture of the two olefin isomers in the ratio >10:1.

The Main isomer has: ¹H NMR δ 0.78 (s, 3H), 1.55 (dd, 3H, J=2.4, 6.6 Hz), 1.93 (m, 2H), 2.17 (m, 1H), 2.38 (m, 1H), 3.37 (s, 3H), 3.82 (m, 1H), 4.66 (m, 2H), 5.21 (m, 1H); ¹³C NMR δ 11.4, 12.3, 20.3, 23.2, 23.3, 24.6, 26.1, 26.3, 28.6, 32.2, 32.6, 32.9, 33.4, 33.6, 34.9, 36.0, 39.8, 44.4, 48.3, 54.5, 55.1, 57.0, 71.6, 94.5, 116.8, 140.0; IR ν_(max) 2927, 1445, 1044 cm⁻¹.

(3α,5α,20S)-1-[3-Methoxymethoxy-13,24-cyclo-18,21-dinorcholan-20-yl]ethanone (77) and (3α,5α,20R)-1-[3-Methoxymethoxy-13,24-cyclo-18,21-dinorcholan-20-yl]ethanone (78)

BH₃ (1.0 M in THF, 1.28 mL, 1.28 mmol) was added to compound 75 (165 mg, 0.43 mmol) in anhydrous THF (15 mL) under N₂ at 0° C. The resultant solution was stirred at room temperature for 3.5 h and cooled to 0° C. Water (0.1 mL) was added to quench the reaction followed by aqueous NaOH (3 N, 2.6 mL) and 30% H₂O₂ (2.6 mL). The reaction mixture was stirred at ambient temperature overnight and extracted with EtOAc. The combined EtOAc extracts were washed with brine until neutral pH and then dried over Na₂SO₄. After solvent removal under reduced pressure, the residue 76 (a mixture of four diastereomers) was used without further purification or characterization.

Jones reagent was added dropwise to a solution of compound 76 in acetone (15 mL) at 0° C. until an orange color persisted. The resultant mixture was stirred at 0-5° C. for 10 min. 2-propanol was added to consume excess oxidant and the acetone was removed under reduced pressure. The residue obtained was dissolved in EtOAc (30 mL), washed with water to neutral pH, and dried over Na₂SO₄. The solvent was removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) to give a mixture of compound 77 and 78 (152 mg, 88%) in the ratio of 3:2. The compounds were further separated by column chromatography (silica gel; hexanes/EtOAc, 30:1).

Compound 77 was obtained as white solid: mp. 106-107° C.; ¹H NMR δ 0.75 (s, 3H), 2.16 (s, 3H), 2.42 (bs, 1H), 3.36 (s, 3H), 3.82 (m, 1H), 4.65 (m, 2H); ¹³C NMR δ 11.3, 18.1, 20.1, 21.6, 22.6, 23.8, 26.2, 27.7, 28.1, 28.5, 32.0, 32.8, 33.6, 33.9, 34.6, 35.9, 39.7, 41.6, 46.0, 49.6, 54.3, 55.1, 57.4, 71.6, 94.5, 211.6; IR ν_(max) 3400, 2928, 1708, 1041 cm⁻¹.

Compound 78 was obtained as white solid: mp. 103-105° C.; ¹H NMR δ 0.78 (s, 3H), 2.06 (m, 1H), 2.10 (s, 3H), 2.61 (m, 1H), 3.37 (s, 3H), 3.83 (m, 1H), 4.66 (m, 2H); ¹³C NMR δ 11.4, 20.2, 20.5, 21.6, 21.9, 22.4, 23.7, 26.3, 27.9, 28.5, 32.0, 32.9, 33.3, 33.6, 34.7, 36.0, 39.8, 42.6, 47.5, 49.4, 54.6, 55.1, 56.7, 71.6, 94.5, 211.8; IR ν_(max) 3392, 2923, 1707, 1041 cm⁻¹.

(3α,5α,20S)-1-[3-Hydroxy-13,24-cyclo-18,21-dinorcholan-20-yl]ethanone (79)

The mixture of compound 77 (32 mg, 80 μmol), LiBF₄ (64 mg, 0.68 mmol), H₂O (0.1 mL) and MeCN (3 mL) was refluxed for 3 h and cooled to room temperature. EtOAc (30 mL) was added and the solution was washed with water and brine and dried over Na₂SO₄. The solvent was removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 7:1) to give compound 79 (27 mg, 95%).

Compound 79 was obtained as white crystals: mp. 187-189° C. (acetone-hexanes); ¹H NMR δ 0.75 (s, 3H), 2.16 (s, 3H), 2.42 (m, 1H), 4.03 (m, 1H); ¹³C NMR δ 11.1, 18.1, 20.1, 21.6, 22.6, 23.8, 27.7, 28.1, 28.5, 29.0, 32.0, 32.1, 33.9, 34.6, 35.8, 36.1, 39.1, 41.6, 46.0, 49.6, 54.3, 57.4, 66.5, 211.7; IR ν_(max) 3401, 2928, 1705 cm⁻¹.

(3α,5α,20R)-1-[3-Hydroxy-13,24-cyclo-18,21-dinorcholan-20-yl]ethanone (80)

Using the same procedure described for the preparation of compound 79 from compound 77, compound 80 (29 mg, 93%) was prepared from compound 78 (35 mg, 87 μmol).

Compound 80 was obtained as white crystals: mp. 228-229° C. (EtOAc-hexanes); ¹H NMR δ 0.78 (s, 3H), 1.83 (m, 1H), 2.05 (m, 1H), 2.10 (s, 3H), 2.62 (m, 1H), 4.04 (m, 1H); ¹³C NMR δ 11.2, 20.2, 20.5, 21.6, 21.9, 22.4, 23.7, 27.9, 28.5, 29.0, 32.1, 32.2, 33.3, 34.7, 35.9, 36.2, 39.2, 42.6, 47.5, 49.4, 54.6, 56.7, 66.5, 211.8; IR ν_(max) 3401, 2927, 1699 cm⁻¹.

(3α,5α)-1-[3-Methoxymethoxy-13,24-cyclo-18,21-dinorchol-20(22)-en-20-yl]ethanone (82)

The mixture of compounds 77 and 78 (100 mg, 0.25 mmol) and NBS (73 mg, 0.41 mmol) in CCl₄ (15 mL) was refluxed under N₂ while being irradiated with a 300 W tungsten lamp for 20 min and then cooled to room temperature. The solvent was partially removed and the residue was purified by column chromatography (silica gel; hexanes/EtOAc, 20:1) to give compound 81 (80 mg, 67%) as a mixture of two diastereomers in the ratio of 1:1.

The mixture of compound 81 (80 mg, 0.17 mmol), Li₂CO₃ (160 mg, 2.16 mmol), and LiBr (80 mg, 0.93 mmol) in DMF (3 mL) was heated at 130° C. under N₂ for 2 h and cooled to room temperature. EtOAc (30 mL) was added and the mixture was washed with water, 3% HCl and water and dried over Na₂SO₄. The solvent was removed and the residue purified by column chromatography (silica gel; hexanes/EtOAc, 20:1) gave compound 82 (42 mg, 63%).

Compound 82 was obtained as white crystals: mp. 157-159° C. (hexanes); ¹H NMR δ 0.80 (s, 3H), 2.27 (s, 3H), 3.37 (s, 3H), 3.83 (m, 1H), 4.66 (m, 2H), 6.78 (t, 1H, J=3.6 Hz); ¹³C NMR δ 11.5, 18.8, 20.0, 23.2, 24.6, 25.5, 26.3, 28.6, 30.5, 32.1, 32.8, 32.9, 33.6, 35.0, 36.0, 39.8, 41.0, 44.4, 54.5, 55.2, 55.5, 71.6, 94.5, 138.7, 143.7, 199.4; IR ν_(max) 2928, 1667, 1435, 1042 cm⁻¹.

(3α,5α)-1-[3-Hydroxy-13,24-cyclo-18,21-dinorchol-20(22)-en-20-yl]ethanone (83)

Using the same procedure described for the preparation of compound 67 from compound 65, compound 83 (16 mg, 95%) was prepared from compound 82 (19 mg, 48 mol).

Compound 83 was obtained as white solid: mp. 198-200° C. (ether-hexanes); ¹H NMR δ 0.79 (s, 3H), 2.27 (s, 3H), 4.04 (m, 1H), 6.78 (t, 1H, J=3.9 Hz); ¹³C NMR δ 11.2, 18.8, 20.0, 23.2, 24.6, 25.5, 28.5, 29.0, 30.5, 32.1, 32.2, 32.8, 35.0, 35.9, 36.2, 39.2, 41.0, 44.4, 54.5, 55.5, 66.5, 138.7, 143.7, 199.4; IR ν_(max) 3315, 2924, 1667, 1252 cm⁻¹.

(3β,5α)-3-Acetyloxy-21-diazopregnan-20-one (85)

Oxalyl chloride (0.12 mL, 1.38 mmol) was added to compound 84 (100 mg, 0.28 mmol) in benzene at 0° C. under N₂ and stirred at room temperature for 4 h. Removal of solvent under reduced pressure gave the acid chloride as a solid. It was used without further purification.

The acid chloride in ether (10 mL) was added to diazomethane (0.2 M in ether, 6 mL) dropwise at 0° C. and stirred at ambient temperature overnight. The solvent was removed under reduced pressure in a hood and the yellow residue obtained was purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) to give compound 85 (84 mg, 79%).

Compound 85 was obtained as a yellow solid: mp. 135-136° C. (133-137° C. in Pettit noted below); ¹H NMR δ 0.66 (s, 3H), 0.82 (s, 3H), 2.02 (s, 3H), 4.68 (m, 1H), 5.18 (s, 1H); ¹³C NMR δ 12.1, 13.3, 21.0, 21.4, 22.8, 24.4, 27.3, 28.4, 31.9, 33.9, 35.4 (2×C), 36.7, 38.6, 44.6, 44.8, 54.1, 54.7, 56.3, 61.4, 73.5, 170.6, 195.1; IR ν_(max) 2937, 2099, 1731, 1637, 1367, 1246 cm⁻¹. (See also, Pettit, G. R., et al., Steroids and Related Natural Products. LIV. Bufadienolides. 7. Synthesis of 3β-Acetoxy-5α-l4α-bufa-20,22-dienolide, J. Org. Chem. 1970, 35, 1398-1404).

(3β,5α)-3-Acetyloxy-18,21-cyclopregnan-20-one (86)

Compound 85 (600 mg, 1.55 mmol) in CH₂Cl₂ (10 mL) was added to Rh₂(OCOCF₃)₄ in CH₂Cl₂ (50 mL) and stirred at room temperature for 10 min. Most solvent was removed under reduced pressure and the residue purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) gave compound 86 (300 mg, 54%).

Compound 86 was obtained as white crystals: mp. 146-148° C.; ¹H NMR δ 0.82 (s, 3H), 2.02 (s, 3H), 4.69 (m, 1H); ¹³C NMR δ 12.2, 21.4, 21.6, 24.2, 26.2, 27.4, 27.7, 28.3, 32.1, 33.9, 34.3, 35.5, 35.7, 36.8, 37.0, 44.5, 51.9, 53.5, 55.5, 58.5, 73.5, 170.7, 222.6; IR ν_(max) 2933, 1733, 1244, 1027 cm⁻¹.

(3(3,5a)-3-Hydroxy-18,21-cyclopregnan-20-one (87)

Compound 86 (300 mg, 0.84 mmol) was dissolved in MeOH (20 mL) and 20% aqueous NaOH (1.0 mL) was added. The solution was refluxed for 20 min and cooled to room temperature. MeOH was removed under reduced pressure and EtOAc (50 mL) was added. The organic layer was washed with water and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue that was purified by column chromatography (silica gel; hexanes/EtOAc, 5:1) to give compound 87 (250 mg, 94%).

Compound 87 was obtained as white crystals: mp. 182-184° C.; ¹H NMR δ 0.80 (s, 3H), 3.59 (m, 1H); ¹³C NMR δ 12.2, 21.6, 24.1, 26.2, 27.6, 28.4, 31.3, 32.2, 34.3, 35.5, 35.6, 36.9, 36.9, 38.0, 44.7, 51.8, 53.5, 55.5, 58.4, 71.0, 222.6; IR ν_(max) 3413, 2923, 1721, 1447, 1042 cm⁻¹.

(3α,5α)-3-Benzoyloxy-18,21-cyclopregnan-20-one (88)

DEAD (40% solution in toluene) was added dropwise to the mixture of compound 87 (250 mg, 0.79 mmol), Ph₃P (250 mg, 0.95 mmol) and PhCO₂H (116 mg, 0.95 mmol) in THF (20 mL) until the yellow color persisted. The yellowish solution was stirred at room temperature for 2 h and most of THF was removed under reduced pressure. The residue obtained was purified by column chromatography (silica gel; hexanes/EtOAc, 10:1) to give compound 88 (290 mg, 87%).

Compound 88 was obtained as white solid: mp. 201-204° C.; ¹H NMR δ 0.85 (s, 3H), 5.29 (m, 1H), 7.46 (t, 2H, J=7.2 Hz), 7.57 (t, 1H, J=7.2 Hz), 8.07 (d, 2H, J=7.2 Hz); ¹³C NMR δ 11.4, 21.2, 24.2, 26.2, 26.2, 27.7, 28.1, 32.1, 32.9, 33.2, 34.3, 35.7, 35.9, 37.0, 40.3, 51.9, 53.6, 55.6, 58.5, 70.5, 128.3 (2×C), 129.5 (2×C), 131.1, 132.7, 165.8, 222.5; IR ν_(max) 2930, 1735, 1714, 1450, 1272, 1113, 714 cm⁻¹.

(3α,5α)-3-Hydroxy-18,21-cyclopregnan-20-one (89)

Compound 88 (290 mg, 0.69 mmol) was dissolved in EtOH (20 mL) and 20% aqueous NaOH (0.8 mL) was added. The solution was refluxed for 20 min and cooled to room temperature. EtOH was removed under reduced pressure and EtOAc (50 mL) was added. The organic layer was washed with water and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue that was purified by column chromatography (silica gel; hexanes/EtOAc, 5:1) to give compound 89 (210 mg, 96%).

Compound 89 was obtained as white crystals: mp. 176-178.5° C. (EtOAc-hexanes); ¹H NMR δ 0.78 (s, 3H), 4.05 (m, 1H); ¹³C NMR δ 11.2, 21.2, 24.2, 26.2, 27.7, 28.3, 28.9, 32.2 (2×C), 34.4, 35.7, 35.8, 36.1, 37.0, 39.0, 51.9, 53.6, 55.7, 58.5, 66.4, 222.7; IR ν_(max) 3307, 2923, 1736, 1448 cm⁻¹.

(3α,5α)-3-Hydroxy-18,21-cyclopregn-18(21)-en-20-one (94) and (3α,5α)-21-bromo-3-hydroxy-18,21-cyclopregn-18(21)-en-20-one (95)

The mixture of compound 88 (168 mg, 0.40 mmol) and pyridinium tribromide (180 mg, 0.56 mmol) in THF (20 mL) was stirred at room temperature for 1.5 h. The solvent was removed under reduced pressure and EtOAc (20 mL) was added. The EtOAc solution was washed with water, 5% Na₂S₂O₃ and water and dried over Na₂SO₄. Solvent removal under reduced pressure gave a residue that was passed through a short column (silica gel; hexanes/EtOAc, 5:1) to give a mixture of 21-bromo-20-one (90) and 21,21-dibromo-20-one (91). The mixture of compounds was used without further separation.

The mixture of compounds 90 and 91 (160 mg, 0.32 mmol), Li₂CO₃ (300 mg), LiBr (150 mg) in DMF (5 mL) was stirred at 130° C. for 6 h and cooled to room temperature. EtOAc (50 mL) was added and the organic layer was washed with water, 5% HCl and water and dried over Na₂SO₄. After the solvent was removed under reduced pressure, the residue was separated by column chromatography (silica gel; hexanes/EtOAc, 12:1) to give partially purified compound 92 (34 mg, 25%) and compound 93 (55 mg, 41%).

Using the same procedure described for the preparation of compound 89 from compound 88, compound 94 (22 mg, 86%) was prepared from compound 92 (34 mg, 81 μmmol) and compound 95 (32 mg, 77%) was prepared from compound 93 (55 mg, 131 μmmol).

Compound 94 was obtained as white crystals: mp. 139-141° C. (EtOAc-hexanes); ¹H NMR 60.86 (s, 3H), 2.31 (d, 1H, J=11.1 Hz), 4.07 (m, 1H), 6.19 (d, 1H, J=6.0 Hz), 7.73 (d, 1H, J=6.0 Hz); ¹³C NMR δ 11.2, 21.9, 26.0, 28.3, 28.8, 29.0, 32.1, 32.3, 35.7, 35.8, 36.0, 36.3, 39.0, 54.0, 54.2, 54.6, 57.4, 66.3, 134.7, 167.3, 212.4; IR ν_(max) 3412, 2926, 1709, 1448 cm⁻¹.

Compound 95 was obtained as white crystals: mp. 220-222.5° C. (EtOAc-hexanes); ¹H NMR δ 0.87 (s, 3H), 2.49 (d, 1H, J=11.4 Hz), 4.08 (m, 1H), 7.81 (s, 1H); ¹³C NMR δ 11.3, 21.9, 26.0, 28.2, 29.0 (2×C), 32.1, 32.2, 35.7, 35.7, 35.8, 36.3, 38.9, 53.2, 54.1 (2×C), 57.0, 66.3, 125.6, 164.7, 203.7; IR ν_(max) 3538, 2919, 1717, 1446 cm⁻¹. MS (ESI) m/z 415 (M⁺+Na⁺), 417 (M⁺+2+Na⁺).

(3α,5α,20E)-3-Hydroxy-18,21-cyclopregnan-20-ylideneacetonitrile (96) and (3α,5α,20Z)-3-Hydroxy-18,21-cyclopregnan-20-ylideneacetonitrile (97)

Using the same procedure described for the preparation of compound 63 and 64 from compound 2a, compound 96 (39 mg, 48%) and 97 (32 mg, 40%) was prepared from compound 89 (75 mg, 0.24 mmol). Compounds 96 and 97 were separated by column chromatography (silica gel; CH₂Cl₂/EtOAc, 30:1).

Compound 96 was obtained as white crystals: mp. 201-202.5° C. (acetone-hexanes); ¹H NMR δ 0.76 (s, 3H), 2.05 (m, 1H), 2.46 (m, 1H), 2.67 (m, 2H), 4.05 (m, 1H), 5.12 (s, 1H); ¹³C NMR δ 11.2, 21.5, 26.1, 27.3, 28.3, 29.0, 31.8, 31.9, 32.2 (2×C), 34.7, 35.8, 36.1, 37.0, 39.0, 53.6, 55.2, 55.3, 56.4, 66.4, 89.9, 117.5, 178.7; IR ν_(max) 3306, 2927, 2214, 1634, 1448 cm⁻¹.

Compound 97 was obtained as white crystals: mp. 226-228° C. (acetone-hexanes); ¹H NMR δ 0.75 (s, 3H), 2.28 (m, 1H), 2.53 (m, 2H), 2.77 (m, 1H), 4.04 (m, 1H), 5.09 (d, 1H, J=1.8 Hz); ¹³C NMR δ 11.2, 21.5, 26.0, 27.5, 28.3, 28.9, 30.9, 32.2 (2×C), 32.8, 34.6, 35.8, 36.1, 37.0, 39.0, 53.6, 54.9, 55.2, 55.3, 66.4, 89.7, 117.7, 179.0; IR ν_(max) 3401, 2922, 2215, 1446 cm⁻¹.

Physical Properties and Spectroscopic Data for Evaluated Compounds in the 5β-Series (3α,5β)-3-Hydroxy-13,24-cyclo-18,21-dinorcholan-20-one (2b)

Compound 2b was obtained as white crystals: mp 220-222° C. (EtOAc-hexanes); ¹H NMR δ 0.93 (s, 3H, 19-CH₃), 2.50 (m, 1H, CHCO), 3.63 (m, 1H, CHOH); ¹³C NMR δ 20.3, 22.1 (2×C), 23.3, 25.1, 26.7, 27.0, 27.1, 30.5, 33.7, 34.6, 35.4, 35.5, 36.3, 37.3, 40.2, 42.0, 49.6, 56.7, 61.5, 71.6, 215.5 (CO); IR ν_(max) 3449, 2921, 1698, 1460, 1037 cm⁻¹. Anal. (C₂₂H₃₄O₂) C, H.

(3α,5β)-3-Hydroxy-13,24-cyclo-18,21-dinorcholan-22-one (3b)

Compound 3b was obtained as white crystals: mp 175-177° C. (EtOAc-hexanes); ¹H NMR δ 0.93 (s, 3H, 19-CH₃), 2.38 (m, 1H, CH₂CO), 2.54 (dd, J=6.0 Hz, J=14.4 Hz, 1H, CH₂CO), 3.65 (m, 1H, CHOH); ¹³C NMR δ 20.4, 23.3 (2×C), 23.6, 26.4, 27.0, 27.7, 30.4, 32.8, 34.6, 35.4, 35.9, 36.3, 36.9, 40.6, 41.2, 41.5, 42.0, 49.0, 55.5, 71.6, 213.4 (CO); IR ν_(max) 3418, 2936, 1714, 1447 cm⁻¹. Anal. (C₂₂H₃₄O₂) C, H.

(3α,5β)-3-Hydroxy-13,24-cyclo-18,21-dinorcholan-23-one (4b)

Compound 4b was obtained as white crystals: mp 197-198° C. (Ether-hexanes); ¹H NMR δ 0.91 (s, 3H, 19-CH₃), 2.50 (m, 1H, CH₂CO), 3.64 (m, 1H, CHOH); ¹³C NMR δ 19.8, 23.4, 24.4, 24.9, 25.2, 26.4, 26.9, 30.5, 34.4, 34.7, 35.2, 35.3, 36.3, 36.5, 40.5 (2×C), 42.0, 44.7, 48.9, 56.3, 71.7, 213.7 (CO); IR ν_(max) 3398, 2927, 1709, 1448, 1039 cm⁻¹. Anal. (C₂₂H₃₄O₂) C, H.

(3α,5β)-3-Hydroxy-13,24-cyclo-18,21-dinorcholan-24-one (5b)

Compound 5b was obtained as white crystals: mp 177-178° C. (Et₂O-hexanes); ¹H NMR δ 0.89 (s, 3H, 19-CH₃), 3.64 (m, 1H, CHOH); ¹³C NMR δ 21.7, 23.6, 23.9 (2×C), 24.0, 25.5, 27.0, 27.1, 30.5, 34.7, 35.3, 35.4, 35.6, 36.5, 40.2, 41.1, 42.2, 49.8, 56.4, 58.5, 71.8, 216.6 (CO); IR ν_(max) 3334, 2937, 1701, 1450, 1037 cm⁻¹. Anal. (C₂₂H₃₄O₂).

(3α,5β)-3-(Acetyloxy)-20-hydroxypregnane-20-carbonitrile (7b)

Compound 7b was prepared using a reported method (See, Slomp, G., Jr. 3,20-Dioxo-Δ⁴-steroid 20-cyanohydrins. U.S. Pat. No. 2,655,517, 1953. Chem. Abstr. 48:60638) and was obtained as a white solid: mp 168-178° C.; ¹H NMR δ 0.95 (s, 3H, 19-CH₃), 0.99 (s, 3H, 18-CH₃), 1.63 (s, 3H, 21-CH₃), 2.03 (s, 3H, CH₃C(O)O), 4.73 (m, 1H, CHOAc); ¹³C NMR δ 13.0, 20.5, 21.4, 23.3, 24.1, 25.1, 26.2, 26.6, 26.9, 30.7, 32.2, 34.6, 35.0, 35.2, 40.3, 40.4, 41.8, 43.6, 55.9, 59.2, 71.7, 74.3, 121.9 (CN), 170.6 (C(O)O).

(3α,5β)-3-(Acetyloxy)-20-oxo-pregnane-18-carbonitrile (8b)

Compound 8b was obtained as a colorless oil: ¹H NMR δ 0.94 (s, 3H, 19-CH₃), 2.04 (s, 3H, CH₃C(O)O), 2.29 (s, 3H, CH₃CO), 2.72 (t, J=9.3 Hz, 1H, CHCOCH₃), 4.73 (m, 1H, CHOAc); ¹³C NMR δ 16.3, 20.6, 21.3, 23.1, 23.2, 23.9, 26.0, 26.5, 26.6, 32.1, 32.4, 34.4, 34.8, 35.8, 36.1, 40.1, 41.4, 46.1, 56.3, 62.0, 73.8, 118.0 (CN), 170.4 (C(O)O), 208.6 (CO).

(3α,5β)-3-(Acetyloxy)-20,20-[1,2-ethanediylbis(oxy)]pregnane-18-carbonitrile (9b)

Compound 9b was obtained as white crystals: mp 138-140° C.; ¹H NMR δ 0.94 (s, 3H, 19-CH₃), 1.29 (s, 3H, 21-CH₃), 2.03 (s, 3H, CH₃C(O)O), 2.24 (d, J=16.8 Hz, 1H, CH₂CN), 2.51 (d, J=16.8 Hz, 1H, CH₂CN), 4.04 (m, 4H, OCH₂CH₂O), 4.72 (m, 1H, CHOAc); ¹³C NMR δ 16.7, 20.5, 21.4, 23.2, 23.2, 23.3, 23.5, 25.9, 26.6, 26.8, 32.2, 34.5, 34.9, 35.5, 36.8, 40.3, 41.6, 43.8, 56.1, 56.5, 63.1, 63.8, 74.1, 110.8 (20-C), 119.8 (CN). 170.5 (C(O)O).

(3α,5β)-3-Hydroxy-13,24-cyclo-18,21-dinorchol-22-en-20-one (11b)

Compound 11b was obtained as white crystals: mp 253-254° C. (EtOAc); ¹H NMR δ 0.93 (s, 3H, 19-CH₃), 3.63 (m, 1H, CHOH), 5.96 (dd, J=3.0 Hz, J=9.9 Hz, 1H, ═CHCO), 6.83 (m, 1H, ═CHCH₂); ¹³C NMR δ 20.3, 23.3, 25.8, 26.3, 26.5, 26.9, 27.3, 30.5, 34.1, 34.6, 35.3, 35.6, 36.3, 40.1, 42.0, 47.6, 56.2, 57.8, 71.6, 127.4 (═CHCO), 148.3 (═CHCH₂), 202.2 (CO); IR ν_(max) 3430, 2921, 1663, 1038 cm⁻¹. Anal. (C₂₂H₃₂O₂) C, H.

(3α,5β)-13,24-Cyclo-18,21-dinorchol-20(22)-en-3-ol (13b)

Compound 13b was obtained as white crystals: mp 168-169° C. (hexanes); ¹H NMR δ 0.94 (s, 3H, 19-CH₃), 3.63 (m, 1H, CHOH), 5.54 (m, 1H, CH═), 5.76 (m, 1H, CH═); ¹³C NMR δ 20.0, 20.2, 21.6, 23.4, 24.8, 26.7, 27.2, 30.6, 30.6, 33.4, 34.7, 35.1, 35.5, 36.5, 40.8, 41.0, 42.2, 46.6, 56.1, 71.8, 124.4 (CH═), 130.8 (CH═).

(3α,5β)-3-Methoxymethoxy-13,24-cyclo-18,21-dinorchol-20(22)-ene (14b)

Compound 14b was obtained as a colorless oil: ¹H NMR δ 0.93 (s, 3H, 19-CH₃), 3.37 (s, 3H, OCH₃), 3.53 (m, 1H, CHOCH₂O), 4.69 (s, 2H, OCH₂O), 5.54 (m, 1H, CH═), 5.75 (m, 1H, CH═); ¹³C NMR δ 19.7, 20.1, 21.6, 23.4, 24.7, 26.7, 27.2, 27.7, 30.6, 33.3, 33.6, 34.8, 35.0, 35.4, 40.7, 40.9, 42.2, 46.6, 55.1, 56.1, 76.8, 94.5 (OCH₂O), 124.4 (CH═), 130.7 (CH═).

(3α,5β)-3-Hydroxy-13,24-cyclo-18,21-dinorchol-20(22)-en-23-one (22c)

Compound 22c was obtained as white crystals: mp 209-211° C. (EtOAc-hexanes); ¹H NMR δ 0.92 (s, 3H, 19-CH₃), 2.35 (d, J=15.9 Hz, 1H, CCH₂CO), 3.64 (m, 1H, CHOH), 5.90 (d, J=9.6 Hz, 1H, ═CHCO), 6.96 (m, 1H, ═CHCH); ¹³C NMR δ 19.7, 23.3, 26.3, 26.4, 26.9, 29.4, 30.4, 34.4, 34.6, 35.1, 35.3, 36.3, 37.9, 40.4, 42.0, 47.3, 47.4, 56.0, 71.6, 127.1 (═CHCO), 152.0 (═CHCH), 200.2 (CO); IR ν_(max) 3446, 2932, 1677, 1451, 1042 cm⁻¹. Anal. (C₂₂H₃₂O₂) C, H.

(3α,5β)-13,24-Cyclo-18,21-dinorchola-20(22),23-diene-3,20-diol, 3,20-diacetate (23b)

Compound 23b was obtained as white crystals: mp 138-139° C.; ¹H NMR δ 0.96 (s, 3H, 19-CH₃), 2.03 (s, 3H, CHOC(O)CH₃), 2.15 (s, 3H, ═CHOC(O)CH₃), 4.74 (m, 1H, CHOAc), 5.56 (d, J=5.7 Hz, 1H, CH═COAc), 5.62 (d, J=9.9 Hz, 1H, CH═CHCH═), 5.84 (dd, J=5.7 Hz, J=9.9 Hz, 1H, CH═CHCH═); ¹³C NMR δ 20.1, 21.2, 21.4, 23.3, 26.6, 26.7, 27.0, 29.7, 32.2, 32.4, 34.7, 35.1, 36.3, 37.6, 40.5, 41.8, 47.9, 48.4, 56.1, 74.2, 107.8 (CH═COAc), 122.4 (═CHCH═COAc), 127.5 (CCH═CH), 154.5 (═COAc), 169.0 (CHOC(O)CH₃), 170.5 (═COC(O)CH₃).

(3α,5β,20R)-13,24-Cyclo-18,21-dinorchol-23-en-3,20-diol, 3-acetate (25a)

Compound 25a was obtained as a colorless oil: ¹H NMR δ 0.96 (s, 3H, 19-CH₃), 2.04 (s, 3H, CH₃C(O)O), 4.11 (m, 1H, CHOH), 4.74 (m, 1H, CHOAc), 5.54 (m, 1H, CH₂CH═), 5.63 (d, J=10.2 Hz, 1H, CCH═); ¹³C NMR δ 20.6, 20.8, 21.4, 23.3, 25.9, 26.6, 26.7, 26.9, 30.7, 32.3, 34.8, 35.1, 35.7, 38.7, 40.8, 41.9, 48.0, 51.1, 55.1, 66.9, 74.3, 124.8 (CH═), 129.5 (CH═), 170.6 (C(O)O).

(3α,5β,20S)-13,24-Cyclo-18,21-dinorchol-23-en-3,20-diol, 3-acetate (25b)

Compound 25b was obtained as a colorless oil: ¹H NMR δ 0.97 (s, 3H, 19-CH₃), 2.04 (s, 3H, CH₃C(O)O), 4.07 (m, 1H, CHOH), 4.74 (m, 1H, CHOAc), 5.65 (m, 1H, CH₂CH═), 5.84 (d, J=10.8 Hz, 1H, CCH═); ¹³C NMR δ 20.8, 21.4, 23.3, 25.9, 26.1, 26.6, 26.7, 27.0, 30.0, 32.3, 34.7, 35.0, 35.3, 39.9, 40.5, 41.8, 42.9, 50.1, 55.7, 68.4, 74.3, 124.1 (CH═), 129.6 (CH═), 170.6 (C(O)O).

(3α,5β)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorchol-23-ene (28b)

Compound 28b was obtained as a colorless oil: ¹H NMR δ 0.96 (s, 3H, 19-CH₃), 2.03 (s, 3H, CH₃C(O)O), 4.73 (m, 1H, CHOAc), 5.66 (bs, 2H, CH═CH); ¹³C NMR δ 20.5, 20.8, 21.2, 21.4, 23.3, 24.6, 26.2, 26.6, 26.7, 27.0, 32.2, 34.7, 35.1, 35.4, 38.6, 40.8, 41.9, 43.4, 43.8, 55.1, 74.3, 128.0 (CH═), 129.5 (CH═), 170.5 (C(O)O).

(3α,5β)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorchol-23-en-22-one (29b)

Compound 29b was obtained as a white solid (contaminated with 10% unidentified impurity): ¹H NMR δ 1.00 (s, 3H, 19-CH₃), 2.04 (s, 3H, CH₃C(O)O), 2.41 (dm, J=17.1 Hz, 1H, CH₂CO), 2.64 (dd, J=4.2 Hz, J=17.1 Hz, 1H, CH₂CO), 4.75 (m, 1H, CHOAc), 6.00 (d, J=10.5 Hz, 1H, ═CHCO), 6.94 (dd, J=2.1 Hz, J=10.5 Hz, 1H, ═CHC); ¹³C NMR δ 20.8, 21.4, 23.3, 26.4, 26.6, 26.7, 26.8, 27.6, 32.2, 34.7, 35.1, 35.7, 36.6, 38.2, 40.6, 41.8, 44.0, 45.6, 56.8, 74.1, 130.1 (═CHCO), 152.1 (═CHC), 170.5 (C(O)O), 199.7 (CO).

(3α,5β)-3-Hydroxy-13,24-cyclo-18,21-dinorchol-23-en-22-one (30b)

Compound 30b was obtained as white crystals: mp 196.5-199° C.; ¹H NMR δ 0.99 (s, 3H, 19-CH₃), 2.41 (dm, J=17.1 Hz, 1H, CH₂CO), 2.64 (dd, J=4.2 Hz, J=17.1 Hz, 1H, CH₂CO), 3.67 (m, 1H, CHOH), 6.00 (d, J=10.5 Hz, 1H, ═CHCO), 6.95 (dd, J=2.1 Hz, J=10.5 Hz, 1H, ═CHC), ¹³C NMR δ 20.8, 23.3, 26.5, 26.8, 27.0, 27.7, 30.5, 34.7, 35.4, 35.7, 36.4, 36.6, 38.2, 40.7, 42.0, 44.0, 45.6, 56.9, 71.6, 130.1 (═CHCO), 152.3 (═CHC), 199.8 (CO); IR ν_(max) 3412, 2933, 1677, 1038 cm⁻¹. Anal. (C₂₂H₃₂O₂).

(3α,5β,23R,24S)-23,24-Epoxy-13,24-cyclo-18,21-dinorcholan-3-ol, acetate (31b)

Compound 31b was obtained as a white solid: mp 125-129° C.; ¹H NMR δ 0.95 (s, 3H, 19-CH₃), 2.03 (s, 3H, CH₃C(O)O), 2.94 (d, J=3.9 Hz, 1H, epoxy 24-H), 3.16 (m, 1H, epoxy 23-H), 4.74 (m, 1H, CHOAc); ¹³C NMR δ 18.2, 19.3, 21.2, 21.4, 23.3, 24.6, 26.2, 26.6, 26.7, 26.9, 32.2, 34.7, 34.9 (2×C), 35.0, 40.7, 40.8, 41.4, 41.8, 54.2, 54.5, 55.8, 74.3, 170.5 (C(O)O).

(3α,5β,23S,24S)-23-Bromo-13,24-cyclo-18,21-dinorcholan-3,24-diol, 3-acetate (32b)

Compound 32b was obtained as a white solid: mp 134-136.5° C.; ¹H NMR δ 0.91 (s, 3H, 19-CH₃), 2.03 (s, 3H, CH₃C(O)O), 3.64 (dd, J=1.8 Hz, J=10.5 Hz, 1H, CHOH), 4.32 (m, 1H, CHBr), 4.73 (m, 1H, CHOAc); ¹³C NMR δ 21.4, 22.6, 23.3, 23.4, 24.9, 24.9, 26.7, 26.9, 27.0, 31.9, 32.3, 33.1, 34.9, 35.2, 35.7, 40.7, 42.1, 47.8, 48.3, 58.3, 63.6, 74.4, 74.5, 170.6 (C(O)O).

(3α,5β,23S)-3-(Acetyloxy)-23-bromo-13,24-cyclo-18,21-dinorcholan-24-one (33b)

Compound 33b was obtained as a white solid: mp 222-225° C.; ¹H NMR δ 0.91 (s, 3H, 19-CH₃), 2.03 (s, 3H, CH₃C(O)O), 4.72 (m, 1H, CHOAc), 4.90 (dd, J=6.3 Hz, J=13.2 Hz, 1H, CHBr); ¹³C NMR δ 21.4, 21.8, 23.6, 23.7, 25.2, 25.6, 26.7, 26.8, 26.9, 32.3, 34.7, 35.1, 35.4, 35.6, 36.3, 41.1, 41.9, 49.5, 56.2, 57.1, 59.9, 74.3, 170.5 (C(O)O), 204.9 (CO).

(3α,5β)-3-(Acetyloxy)-13,24-cyclo-18,21-dinorchol-22-en-24-one (34b)

Compound 34b was obtained as white crystals: mp 146-148° C.; ¹H NMR δ 1.01 (s, 3H, 19-CH₃), 2.03 (s, 3H, CH₃C(O)O), 4.74 (m, 1H, CHOAc), 5.80 (dd, J=2.7 Hz, J=10.2 Hz, 1H, ═CHCO), 6.63 (m, 1H, ═CHCH₂); ¹³C NMR δ 20.3, 21.4, 23.6, 24.4, 26.7 (2×C), 26.9, 27.0, 27.8, 32.4, 32.8, 34.8, 35.2, 35.7, 40.5, 42.1, 45.2, 53.5, 57.2, 74.5, 129.4 (═CHCO), 144.5 (═CHCH₂), 170.5 (C(O)O), 203.8 (CO).

(3α,5β)-3-Hydroxy-13,24-cyclo-18,21-dinorchol-22-en-24-one (35b)

Compound 35b was obtained as white crystals mp 222-223° C. (EtOAc-hexanes); ¹H NMR δ 1.00 (s, 3H, 19-CH₃), 3.65 (m, 1H, CHOH), 5.80 (dd, 1H, J=3.0 Hz, J=10.2 Hz, ═CHCO), 6.62 (m, 1H, ═CHCH₂); ¹³C NMR δ 20.3, 23.6, 24.4, 26.7, 27.1 (2×C), 27.8, 30.6, 32.9, 34.8, 35.5, 35.7, 36.5, 40.5, 42.2, 45.2, 53.5, 57.2, 71.8, 129.4 (═CHCO), 144.5 (═CHCH₂), 204.0 (CO); IR ν_(max) 3418, 2861, 1661, 1038 cm⁻¹. Anal. (C₂₂H₃₂O₂).

EXAMPLE 26 [³⁵S]-TBPS Binding Methods

Rat brain cortical membranes were prepared with minor modifications of the method previously reported. (Hawkinson, J. E., et al., Correlation of Neuroactive Steroid Modulation of [ ³⁵ S]t-Butylbicyclophosophorothionate and [ ³ H]Flunitrazepam Binding and γ-Aminobutyric Acid _(A) Receptor Function, Mol. Pharmacol., 1994, 46, 977-985). Briefly, frozen rat cerebral cortices (Pel-freez, Rogers, Ak.) were thawed and homogenized in 10 volumes of ice-cold 0.32 M sucrose using a glass/Teflon pestle. The homogenate was centrifuged at 1500×g for 10 min at 4° C. The resultant supernatant was centrifuged at 10,000×g for 30 min at 4° C. The pellet (P2) from this centrifugation was resuspended in 200 mM NaCl, 50 mM potassium phosphate buffer, pH 7.4, and centrifuged at 10,000×g for 20 min at 4° C. This washing procedure was done a total of three times, and then pellets were resuspended in buffer (˜4 mL/brain) using a glass/Teflon pestle. The membrane suspension was aliquoted, frozen in liquid nitrogen, and stored at −80° C. prior to use.

[³⁵S]-TBPS Binding assays were done according to the procedure described previously (Hawkinson, J. E., et al., Correlation of Neuroactive Steroid Modulation of [ ³⁵ S]t-Butylbicyclophosophorothionate and [ ³ H]Flunitrazepam Binding and γ-Aminobutyric Acid _(A) Receptor Function, Mol. Pharmacol., 1994, 46, 977-985) with modifications. Briefly, aliquots of membrane solution (0.5 mg/mL final protein concentration in assay) were incubated with 5 μM GABA, 2 nM [³⁵S]-TBPS (45-120 Ci/mmol), and 5 μL aliquots of steroid in DMSO solution (final assay concentrations ranged from 1 nM to 10 μM), and brought to a final volume of 1 mL with 200 mM NaCl, 50 mM potassium phosphate buffer, pH 7.4. Control binding was defined as binding observed in the presence of 0.5% DMSO and the absence of steroid. Nonspecific binding was defined as binding observed in the presence of 200 μM picrotoxinin and ranged from 6.1 to 14.3% of total binding. Assay tubes were incubated for 2 hr at room temperature. A Brandel (Gaithersburg, Md.) cell harvester was used for filtration of the assay tubes through Whatman/GF/C glass filter paper. Filter paper was rinsed with 4 mL of ice-cold buffer three times. Radioactivity bound to the filters was read by liquid scintillation counter and data was fit using Sigma Plot version 3.0 to the Hill equation f=R _(max)/{1+([conc]/IC ₅₀)^(n)}  i.

Where R_(max) is the maximal effect, [conc] is steroid concentration, IC₅₀ is the half-maximal inhibitor concentration and n is the Hill coefficient. Each data point was determined in triplicate and 2-3 full concentration-response curves were generated for each steroid.

TABLE 1 Displacement of [³⁵S]-TBPS binding by Cyclosteroids. Compound IC₅₀ (nM)^(a) nHill 5α-Steroids  1a; 20-oxo 74 ± 7 0.89 ± 0.06  5a; 24-oxo 301 ± 20 1.01 ± 0.06  4a; 23-oxo 334 ± 17 1.14 ± 0.05  2a; 20-oxo 514 ± 64 0.84 ± 0.08  3a; 22-oxo 1,440 ± 100  0.95 ± 0.06 35a; Δ²²-24-one 197 ± 23 1.03 ± 0.10 21c; Δ²⁰⁽²²⁾-23-one 243 ± 11 0.89 ± 0.03 11a; Δ²²-20-one 373 ± 20 1.17 ± 0.06 30a; Δ²³-22-one 1260 ± 100 1.00 ± 0.07 19a; (22S,23S)-epoxy- 370 ± 42 0.97 ± 0.09 20-one 19b; (22R,23R)-epoxy- 313 ± 18 1.10 ± 0.06 20-one 39; 20-CN (eq) 1670 ± 138 1.16 ± 0.10 40; 20-CN (ax) 173 ± 12 0.97 ± 0.06 44; 22-CN (eq) 585 ± 30 0.86 ± 0.03 45; 22-CN (ax)  44300 ± 21300 0.42 ± 0.11 49; 23-CN (ax) 574 ± 26 1.20 ± 0.06 50; 23-CN (eq) 482 ± 20 1.09 ± 0.04 13a; Δ²⁰⁽²²⁾-ene 569 ± 28 1.15 ± 0.05 51; 20-[exo-CH₂] 181 ± 9  0.96 ± 0.04 53; 22-[exo-CH₂] 107000 ± 29600 0.47 ± 0.06 57; Δ²⁰⁽²²⁾-20-CN 433 ± 30 1.05 ± 0.06 60; Δ^(20(22),23)-diene 467 ± 26 1.04 ± 0.05 61; Δ²³-ene* 2000 ± 190 0.94 ± 0.08 63; exo-[CHCN]   11 ± 1.8 0.90 ± 0.08 64; exo-[CHCN] 1,080 ± 136  1.10 ± 0.14 67; 20-OH (ax) 613 ± 92 0.83 ± 0.09 68; 20-OH (eq) 1,540 ± 320  0.68 ± 0.09 69; 20-OMe (ax) 353 ± 38 1.07 ± 0.10 70; 20-OMe (eq) 868 ± 78 1.15 ± 0.10 71; (20R,22S)-epoxide 596 ± 71 1.06 ± 0.11 72; (20S,22R)-epoxide 323 ± 25 0.92 ± 0.05 73; exo-(20S)-epoxide 1,290 ± 83   1.66 ± 0.16 74; exo-(20R)-epoxide 64 ± 9 0.99 ± 0.11 79; 20-(acetyl) (ax) 93 ± 9 1.07 ± 0.09 80; 20-(acetyl) (eq) 2,060 ± 340  0.91 ± 0.13 83; Δ²⁰⁽²²⁾-20-(acetyl) 3,190 ± 398  1.64 ± 0.31 89; 20-one 204 ± 36 0.82 ± 0.10 94; Δ¹⁸⁽²¹⁾-20-one 745 ± 75 0.86 ± 0.07 95; Δ¹⁸⁽²¹⁾-20-one, 21-Br  94 ± 17 1.05 ± 0.16 96; exo-[CHCN] 168 ± 32 0.90 ± 0.13 97; exo-[CHCN] 17,200 ± 6,190 0.44 ± 0.10 5β-Steroids  1b; 20-oxo  71 ± 18 0.57 ± 0.06  5b; 24-oxo 329 ± 35 0.95 ± 0.08  4b; 23-oxo  899 ± 150 0.89 ± 0.11  2b; 20-oxo 1,780 ± 180  1.36 ± 0.16  3b; 22-oxo 3,230 ± 640  0.73 ± 0.11 35b; Δ²²-24-one 105 ± 12 0.90 ± 0.07 22c; Δ²⁰⁽²²⁾-23-one 268 ± 43 0.64 ± 0.05 11b; Δ²²-20-one 1,570 ± 140  1.15 ± 0.10 30b; Δ²³-22-one 4750 ± 970 0.95 ± 0.18 13b; Δ²⁰⁽²²⁾-ene  484 ± 103 0.81 ± 0.11 52; 20-[exo-CH₂] 213 ± 21 0.92 ± 0.07 ^(a)Results presented are from duplicate experiments performed in triplicate. Error limits are calculated as standard error of the means.

EXAMPLE 27 Xenopus Oocyte Electrophysiological Methods

Stage V-VI oocytes were harvested from sexually mature female Xenopus laevis (Xenopus One, Northland, Mich.) under 0.1% tricaine (3-aminobenzoic acid ethyl ester) anesthesia. Oocytes were defolliculated by shaking for 20 min at 37° C. in collagenase (2 mg/ml) dissolved in calcium-free solution containing (in mM): 96 NaCl, 2 KCl, 1 MgCl₂, and 5 HEPES at pH 7.4. Capped mRNA, encoding rat GABA_(A) receptor α1, β2 and γ2L subunits was transcribed in vitro using the mMESSAGE mMachine Kit (Ambion, Austin, Tex.) from linearized pBluescript vectors containing receptor coding regions. Subunit transcripts were injected in equal parts (20-40 ng total RNA) 8-24 hours following defolliculation. Oocytes were incubated up to 5 days at 18° C. in ND96 medium containing (in mM): 96 NaCl, 1 KCl, 1 MgCl₂, 2 CaCl₂ and 5 HEPES at pH 7.4, supplemented with pyruvate (5 mM), penicillin (100 U/ml), streptomycin (100 μg/ml) and gentamycin (50 μg/ml). The cDNAs for the rat GABA_(A)-receptor subunits were originally provided by A. Tobin, University of California, Los Angels (α1), P. Malherbe, Hoffman-La Roche, Switzerland (β2), C. Fraser, National Institute on Alcohol Abuse and Alcoholism (γ2L).

Two-electrode voltage-clamp experiments were performed with a Warner OC725 amplifier 2-5 days following RNA injection. The extracellular recording solution was ND96 medium with no supplements. Intracellular recording pipettes were filled with 3 M KCl and had open tip resistances of ˜1 MΩ. Drugs were applied from a common tip via a gravity-driven multibarrel drug-delivery system. Steroids were simultaneously co-applied with GABA. Cells were clamped at −70 mV for all experiments, and peak current during 20 s drug applications was measured. Data acquisition and analysis were performed with pCLAMP software (Axon Instruments, CA). Statistical differences were determined using a two-tailed Student's t-test.

TABLE 2 Modulation of rat α1β2γ2 GABA_(A) Receptor Function by Cyclosteroids. Oocyte Electrophysiology^(a) Compound 0.1 μM 1 μM 10 μM Gating (10 μM) 5α-Steroids  1a; 20-oxo^(b) 1.26 ± 0.14 3.89 ± 1.34 9.65 ± 3.87 0.37 ± 0.07  5a; 24-oxo 1.22 ± 0.23 3.05 ± 0.79 10.73 ± 1.87  0.39 ± 0.69  4a; 23-oxo 1.39 ± 0.38 1.64 ± 0.15 6.49 ± 0.59 0.32 ± 0.01  2a; 20-oxo 1.01 ± 0.03 1.44 ± 0.03 2.28 0.05   0 ± 0.1  3a; 22-oxo 1.30 ± 0.15 1.61 ± 0.22 2.93 ± 0.68 0.06 ± 0.06 35a; Δ²²-24-one 1.98 ± 0.25 8.33 ± 0.75 9.45 ± 4.19 0.07 ± 0.10 21c; Δ²⁰⁽²²⁾-23-one 1.59 ± 0.14 5.53 ± 0.66 16.58 ± 2.45  0.35 ± 0.12 11a; Δ²²-20-one 1.49 ± 0.20 5.87 ± 1.52 9.07 ± 1.86 0.72 ± 0.03 30a; Δ²³-22-one 1.12 ± 0.08 1.54 ± 0.30 5.07 ± 0.98 −0.04 ± 0.05   19a; (22S,23S)- 1.47 ± 0.17 1.92 ± 0.23 8.90 ± 2.10 0.23 ± 0.24 epoxy-20-one 19b; (22R,23R)- 1.13 ± 0.02 2.11 ± 0.26 5.47 ± 0.62 0.21 ± 0.02 epoxy-20-one 39; 20-N (eq) 1.04 ± 0.03 1.12 ± 0.08 1.70 ± 0.10 0.04 ± 0.04 40; 20-CN (ax) 1.06 ± 0.03 1.23 ± 0.02 1.27 ± 0.02 −0.01 ± 0.01   44; 22-CN (eq) 1.19 ± 0.02 1.14 ± 0.13 4.01 ± 0.42 0.03 ± 0.01 45; 22-CN (ax) 0.90 ± 0.02 0.82 ± 0.02 0.87 ± 0.01 −0.01 ± 0     49; 23-CN (ax) — — 1.3 ± 0.1 — 50; 23-CN (eq) — — 2.1 ± 0.2 — 13a; Δ²⁰⁽²²⁾-ene 1.53 ± 0.45 2.12 ± 0.40 2.68 ± 0.42 −0.32 ± 0.15   51; 20-[exo-CH₂] 0.90 ± 0.15 0.93 ± 0.08 0.95 ± 0.05 −0.06 ± 0.06   53; 22-[exo-CH₂] — — 1.05 ± 0.04 — 57; Δ²⁰⁽²²⁾-20-CN 0.91 ± 0.03 0.96 ± 0.04 3.18 ± 0.24 0.01 ± 0.02 60; Δ^(20(22),23)-diene — — 1.1 ± 0.1 — 61; Δ²³-ene* 1.28 ± 0.08 1.47 ± 0.10 1.72 ± 0.26 0.19 ± 0.10 63; exo-[CHCN] 6.29 ± 1.71 12.34 ± 3.28  17.82 ± 3.75  0.01 ± 0.02 64; exo-[CHCN] 1.19 ± 0.04 1.27 ± 0.03 1.74 ± 0.11 0.03 ± 0.04 67; 20-OH (ax) 0.89 ± 0.03 0.94 ± 0.08 1.37 ± 0.15 −0.01 ± 0.00   68; 20-OH (eq) 0.74 ± 0.05 0.74 ± 0.05 0.79 ± 0.04 0.01 ± 0.02 69; 20-OMe (ax) 0.90 ± 0.04 1.26 ± 0.09 1.72 ± 0.28 0.00 ± 0.00 70; 20-OMe (eq) 0.74 ± 0.01 0.87 ± 0.02 1.02 ± 0.03 0.00 ± 0.00 71; (20R,22S)- 0.90 ± 0.05 1.05 ± 0.09 1.94 ± 0.23 0.00 ± 0.00 epoxide 72; (20S,22R)- 0.90 ± 0.15 2.20 ± 0.25 6.39 ± 1.33 −0.01 ± 0.04   epoxide 73; exo-(20S)-epoxide 0.88 ± 0.05 2.54 ± 0.40 4.84 ± 1.05 −0.02 ± 0.04   74; exo-(20R)-epoxide 1.61 ± 0.18 5.46 ± 1.21 4.53 ± 0.75 −0.01 ± 0.01   79; 20-(acetyl) (ax) 1.00 ± 0.08 1.13 ± 0.15 1.70 ± 0.12 −0.06 ± 0.04   80; 20-(acetyl) (eq) 0.85 ± 0.02 0.77 ± 0.03 0.93 ± 0.07 0.01 ± 0.01 83; Δ²⁰⁽²²⁾-20 (acetyl) 0.89 ± 0.02 0.86 ± 0.04 1.15 ± 0.04 0.00 ± 0.00 89; 20-one 0.81 ± 0.02 1.02 ± 0.07 4.54 ± 0.64 0.01 ± 0.00 94; Δ¹⁸⁽²¹⁾-20-one 0.96 ± 0.02 1.41 ± 0.09 2.78 ± 0.13 −0.04 ± 0.02   95; Δ¹⁸⁽²¹⁾-20-one, 21-Br 1.25 ± 0.08 1.99 ± 0.20 8.75 ± 1.92 0.02 ± 0.02 Br 96; exo-[CHCN] 1.40 ± 0.21 2.33 ± 0.30 2.90 ± 0.29 0.03 ± 0.03 97; exo-[CHCN] 0.88 ± 0.07 0.87 ± 0.15 1.10 ± 0.08 −0.02 ± 0.06   5β-Steroids  1b; 20-oxo 1.20 ± 0.10 2.82 ± 0.51 9.77 ± 2.15 0.61 ± 0.03  5b; 24-oxo 1.26 ± 0.05 3.45 ± 0.29 10.42 ± 1.65  0.04 ± 0.02  4b; 23-oxo 0.97 ± 0.03 1.03 ± 0.08 3.17 ± 0.42 0.01 ± 0.01  2b; 20-oxo 0.93 ± 0.06 1.12 ± 0.14 1.51 ± 0.13 −0.25 ± 0.21    3b; 22-oxo 0.97 ± 0.01 1.11 ± 0.14 2.65 ± 0.33 −0.10 ± 0.06   35b; Δ22-24-one 1.36 ± 0.60 3.15 ± 1.19 21.38 ± 11.08 0.20 ± 0.19 22c; Δ20(22)-23-one 1.07 ± 0.10 1.83 ± 0.25 4.50 ± 0.46 −0.02 ± 0.01   11b; Δ22-20-one 1.07 ± 0.17 1.17 ± 0.11 2.34 ± 0.37 0.11 ± 0.04 30b; Δ23-22-one 1.87 ± 0.24 1.80 ± 0.25 4.44 ± 0.87 0.26 ± 0.31  1b; 20-oxo 1.20 ± 0.10 2.82 ± 0.51 9.77 ± 2.15 0.06 ± 0.03 13b; Δ²⁰⁽²²⁾-ene 1.44 ± 0.17 2.09 ± 0.35 3.48 ± 1.01 −0.05 ± 0.09   52; 20-[exo-CH₂] 1.57 ± 0.16 3.47 ± 0.50 6.22 ± 0.92 −0.02 ± 0.02   ^(a)The GABA concentration used for the control response was 2 μM. Each compound was evaluated on at least four different oocytes at the concentrations indicated, and the results reported are the ratio of the currents measured in the presence/absence of added compound. (G) represents direct current gated by 10 μM compound in the absence of GABA, and this current is reported as the ratio of compound only current/2 μM GABA current. Error limits are calculated as standard error of the means. ^(b)Values reported are from Covey, D., et al., Neurosteroid Analogues. 8. Structure-Activity Studies of N-Acylated 17a-Aza-D-homosteroid Analogues of the Anesthetic Steroids (3α,5α)- and (3α,5β)-3-Hydroxypregnan-20-one, J. Med. Chem., 2000, 43, 3201-3204.

Generally, FIG. 1 depicts the potentiation of electrophysiological responses to GABA by cyclosteroids using two current traces (chloride currents) (FIGS. 1A and 1B) and two tables (FIGS. 1C and 1D). In particular, FIG. 1A is a current trace (chloride current) depicting GABA currents potentiated by 5α-reduced cyclosteroids. The current trace depicts a two-electrode voltage-clamp recording (−70 mV) from an oocyte showing the response to 2 μM GABA alone and in the presence of 500 nM test compound 35a and in the presence of reference compound 1a. At this concentration, effects of the steroids were readily reversible as shown by the GABA recovery panel. FIG. 1B depicts an analogous experiment in another oocyte showing effects of 56-reduced compounds, 35b and 1b. FIG. 1C depicts a table of chloride current versus specific compounds, which summarizes the effects of certain cyclosteroids tested at 500 nM against the response to 2 μM GABA alone (dotted line denotes the normalized response to GABA alone). FIG. 1D depicts a similar summary table for the 56-reduced series.

EXAMPLE 28 Tadpole Behavioral Methods

Tadpole LRR was measured as described previously. (See, Wittmer, L. L., et al., Enantioselectivity of steroid-induced γ-aminobutyric acidA receptor modulation and anesthesia, Mol. Phar., 1996, 50:1581-1586). Briefly, groups of 10 early prelimb-bud stage Xenopus laevis tadpoles (Nasco, Fort Atkinson, Wis.) were placed in 100 mL of oxygenated Ringer's stock solution containing various concentrations of compound. Compounds were added from a 10 mM DMSO stock (final concentration of DMSO in test solutions 0.1%). After equilibrating at room temperature for 3 h, tadpoles were evaluated using the LRR and LSR behavioral endpoints. LRR was defined as failure of the tadpole to right itself within 5 sec after being flipped by a smooth glass rod. LSR was defined as failure of the tadpole to swim when touched by a smooth glass rod. In general, the tadpoles regained their righting and swimming reflexes when placed in fresh oxygenated Ringer's solution. Control beakers containing up to 0.6% DMSO produced no LRR or LSR in tadpoles.

Tadpole LRR and LSR concentration-response curves were fit using Sigma Plot version 3.0 to the Hill equation f=R _(max)/{1+([conc]/EC ₅₀)^(n)}

where R_(max) is the maximum effect, [conc] is the steroid concentration, EC₅₀ is the half-maximal effective concentration, and n is the Hill coefficient.

TABLE 3 Cyclosteroid effects on tadpole righting and swimming reflexes. LSR Compounds LRRa ED₅₀ (μM) LRR NHill LSR^(b) EC₅₀ (μM) nHill 5α-Steriods  1a; 20-one 0.42 ± 0.04 −1.83 ± 0.32 5.50 ± 0.48 −7.5 ± 1.1  5a; 24-one 0.32 ± 0.02 −1.75 ± 0.17 1.73 ± 0.03 −36.5 ± 0.07  4a; 23-one 1.12 ± 0.36 −1.75 ± 0.83 3.58 ± 1.08 −16.7 ± 28.3  2a; 20-one 1.36 ± 0.20 −2.51 ± 0.76 5.45 ± 0.07 −33.5 ± 0.1   3a; 22-one 2.37 ± 0.47 −2.02 ± 0.64 None @ 10 — 35a; Δ²³-24-one 1.02 ± 0.0  −17.1 ± 0.91 2.66 ± 0.0  −24.2 ± 0.0  21c; Δ²⁰ ⁽²²⁾-23-one 1.28 ± 0.38 −1.16 ± 0.26 10.0 ± 0.0  −17.0 ± 0.0  11a; Δ²²-20-one 3.38 ± 0.67 −2.79 ± 1.89 None @ 10 — 30a; Δ²³-22-one 0.73 ± 0.16 −1.57 ± 0.43 5.48 ± 0.09 −33.5 ± 0.1  19a; (22S,23S)- 1.75 ± 0.46 −1.60 ± 0.49 10.0 ± 0.0  −17.0 ± 0.04 epoxy-20-one 19b; (22R,23R)- 0.96 ± 0.29 −1.14 ± 0.27 10.0 ± 0.0  −17.0 epoxy-20-one 31a; (23R,24R)- — — — — epoxide** 39; 20-CN (eq) 0.49 ± 0.09 −1.21 ± 0.22 None @ 10 — 40; 20-CN (ax) >10 — None @ 10 — 44; 22-CN (eq) 0.30 ± 0.03 −1.81 ± 0.31 6.28 ± 1.08 −2.98 ± 0.47 45; 22-CN (ax) >10 — None @ 10 — 49; 23-CN (ax) 0.35 ± 0.09 −1.49 ± 0.49 >10 — 50; 23-CN (eq) 0.35 ± 0.07 −2.11 ± 0.84 0.95 ± 0.01 −15.7 ± 0.43 13a; Δ²⁰⁽²²⁾-ene >10 — None @ 10 — 51; 20-[exo-CH₂] >10 — None @ 10 — 53; 22-[exo-CH₂] — — — — 57; Δ²⁰⁽²²⁾-20-CN    0.42 ±0.10 None @ 10 — 60; Δ^(20(22),23)-diene 2.70 ± 0.72 −1.63 ± 0.49 >10 — 61; Δ²³-ene* None @ 10 — None @ 10 — 63; exo-[CHCN] 0.04 ± 0.00  −3.5 ± 0.54 0.08 ± 0.02 −2.33 ± 1.12 64; exo-[CHCN] 0.68 ± 0.15 −1.68 ± 0.48 10.2 ± 0.00 −11.4 ± 0.02 67; 20-OH (ax) None @ 10 — None @ 10 — 68; 20-OH (eq) >10 — None @ 10 — 69; 20-OMe (ax) None @ 10 — None @ 10 — 70; 20-OMe (eq) >10 — None @ 10 — 71; (20R,22S)- None @ 10 — None @ 10 — epoxide 72; (20S,22R)- 19.3 ± 30.8 −1.01 ± 0.52 None @ 10 — epoxide 73; exo-(20S)- 4.00 ± 1.08 −1.44 ± 0.28 None @ 10 — epoxide 74; exo-(20R)-epoxide >10 — None @ 10 — epoxide 79; 20-(acetyl) (ax) None @ 10 — None @ 10 — 80; 20-(acetyl) (eq) None @ 10 — None @ 10 — 83; Δ²⁰⁽²²⁾-20-(acetyl) 7.20 ± 6.62 −1.21 ± 0.41 None @ 10 — 89; 20-one 2.63 ± 0.07 −3.16 ± 0.35 5.48 ± 0.15 −33.4 ± 0.13 94; Δ¹⁸⁽²¹⁾-20-one 3.37 ± 0.16 −14.8 ± 6.18 9.52 ± 0.00 −18.8 ± 0.00 95; Δ¹⁸⁽²¹⁾-20-one, 21-Br 0.29 ± 0.04 −1.89 ± 0.51 0.55 ± 0.09 −33.5 ± 0.06 21-Br 96; exo-[CHCN] 2.77 ± 1.16 −0.98 ± 0.19 None @ 10 — 97; exo-[CHCN] >10 — None @ 10 — 5β-Steriods  1b; 20-one 0.063 ± 0.003 −1.54 ± 0.12 0.30 ± 0.0  −6.93 ± 0.47  5b; 24-one 0.40 ± 0.12 −4.97 ± 5.29 0.89 ± 0.0  −18.2 ± 0.4   4b; 23-one 1.44 ± 0.02 −3.02 ± 0.09 3.55 ± 1.15 −17.5 ± 33.6  2b; 20-one 0.94 ± 0.55 −1.23 ± 0.64 5.48 ± 0.08 −33.5 ± 0.1   3b; 22-one 2.47 ± 0.53 −1.86 ± 0.57 9.43 ± 0.06 −18.7 ± 0.6  35b; Δ²³-24-one 0.40 ± 0.13 −4.97 ± 5.75 1.00 ± 0.0  −18.6 ± 0.1  22c; Δ²⁰⁽²²⁾-23-one 1.05 ± 0.00 −16.6 ± 0.9  2.72 ± 0.01 −22.1 ± 0.7  11b; Δ²²-20-one 2.56 ± 1.39 −1.59 ± 0.95 8.95 ± 0.01 −19.8 ± 0.01 30b; Δ²³-22-one 0.56 ± 0.9  −1.50 ± 0.27    5.48 −33.5 ± 0.1  13b; Δ²⁰⁽²²⁾-ene 1.28 ± 1.80 −0.64 ± 0.36 >10 — 52; 20-[exo-CH₂] 4.88 ± 1.12 −1.80 ± 0.55 >10 — ^(a)LRR = Loss of righting response. Error limits are calculated as standard error of the means. ^(b)LSR = Loss of swimming response. Error limits are calculated as standard error of the means.

EXAMPLE 29 Elemental Analysis

 2a Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 79.79 H, 10.50  3a Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 80.00 H, 10.32  4a Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 80.13 H, 10.16  5a Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 79.85 H, 10.21  7a Anal. For C₂₄H₃₇NO₃ Calcd. C, 74.38 H, 9.62 N, 3.61 Found C, 74.50 H, 9.50 N, 3.50  8a Anal. For C₂₄H₃₅NO₃ Calcd. C, 74.77 H, 9.15 N, 3.63 Found C, 74.67 H, 9.37 N, 3.44  9a Anal. For C₂₆H₃₉NO₄ Calcd. C, 72.69 H, 9.15 N, 3.26 Found C, 72.47 H, 8.97 N, 3.13 11a Anal. For C₂₂H₃₂O₂ Calcd. C, 80.44 H, 9.82 Found C, 80.21 H, 9.89 13a Anal. For C₂₂H₃₄O Calcd. C, 84.02 H, 10.90 Found C, 84.19 H, 10.92 14a Anal. For C₂₄H₃₈O₂ Calcd. C, 80.39 H, 10.68 Found C, 80.17 H, 10.59 19a Anal. For C₂₂H₃₂O₃ Calcd. C, 76.70 H, 9.36 Found C, 76.57 H, 9.50 19b Anal. For C₂₂H₃₂O₃ Calcd. C, 76.70 H, 9.36 Found C, 76.86 H, 9.24 21a Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 80.05 H, 10.27 21c Anal. For C₂₂H₃₂O₂ Calcd. C, 80.44 H, 9.82 Found C, 80.19 H, 9.63 23a Anal. For C₂₆H₃₆O₄ Calcd. C, 75.69 H, 8.80 Found C, 75.42 H, 8.69 24a Anal. For C₂₄H₃₆O₃ Calcd. C, 77.38 H, 9.74 Found C, 77.41 H, 9.83 24b Anal. For C₂₄H₃₆O₃ Calcd. C, 77.38 H, 9.74 Found C, 77.18 H, 9.57 28a Anal. For C₂₄H₃₆O₂ Calcd. C, 80.85 H, 10.18 Found C, 80.77 H, 10.12 30a Anal. For C₂₂H₃₂O₂ Calcd. C, 80.44 H, 9.82 Found C, 80.32 H, 9.83 32a Anal. For C₂₄H₃₇BrO₃ Calcd. C, 63.57 H, 8.22 Found C, 63.58 H, 8.36 33a Anal. For C₂₄H₃₅BrO₃ Calcd. C, 63.85 H, 7.81 Found C, 63.66 H, 8.00 34a Anal. For C₂₄H₃₄O₃ Calcd. C, 77.80 H, 9.25 Found C, 78.00 H, 9.12 35a Anal. For C₂₂H₃₂O₂ Calcd. C, 80.44 H, 9.82 Found C, 80.63 H, 9.70  2b Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 80.19 H, 10.15  3b Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 79.90 H, 10.23  4b Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 80.10 H, 10.15  5b Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 80.10 H, 10.43 11b Anal. For C₂₂H₃₂O₂ Calcd. C, 80.44 H, 9.82 Found C, 80.55 H, 9.77 22c Anal. For C₂₂H₃₂O₂ Calcd. C, 80.44 H, 9.82 Found C, 80.58 H, 9.87 30b Anal. For C₂₂H₃₂O₂ Calcd. C, 80.44 H, 9.82 Found C, 80.60 H, 9.85 35b Anal. For C₂₂H₃₂O₂ Calcd. C, 80.44 H, 9.82 Found C, 80.56 H, 9.94 39 Anal. For C₂₃H₃₅NO₃ Calcd. C, 80.88 H, 10.33 N, 4.10 Found C, 81.03 H, 10.26 N, 4.15 40 Anal. For C₂₃H₃₅NO₃ Calcd. C, 80.88 H, 10.33 N, 4.10 Found C, 80.94 H, 10.14 N, 4.14 41 Anal. For C₂₄H₃₆O₃ Calcd. C, 77.38 H, 9.74 Found C, 77.16 H, 9.59 44 Anal. For C₂₃H₃₅NO Calcd. C, 80.88 H, 10.33 N, 4.10 Found C, 80.67 H, 10.16 N, 4.07 46 Anal. For C₂₄H₃₆O₃ Calcd. C, 77.38 H, 9.74 Found C, 77.44 H, 9.52 49 Anal. For C₂₃H₃₅NO Calcd. C, 80.88 H, 10.33 N, 4.10 Found C, 80.65 H, 10.33 N, 4.07 50 Anal. For C₂₃H₃₅NO Calcd. C, 80.88 H, 10.33 N, 4.10 Found C, 80.60 H, 10.33 N, 3.80 51 Anal. For C₂₃H₃₆O Calcd. C, 84.09 H, 11.04 Found C, 84.19 H, 11.00 61 Anal. For C₂₂H₃₄O Calcd. C, 84.02 H, 10.90 Found C, 84.20 H, 10.84 63 Anal. For C₂₄H₃₅NO Calcd. C, 81.53 H, 9.98 N, 3.96 Found C, 81.70 H, 9.91 N, 3.95 64 Anal. For C₂₄H₃₅NO Calcd. C, 81.53 H, 9.98 N, 3.96 Found C, 81.48 H, 10.10 N, 3.95 65 Anal. For C₂₄H₄₀O₃ Calcd. C, 76.55 H, 10.71 Found C, 76.58 H, 10.83 66 Anal. For C₂₄H₄₀O₃ Calcd. C, 76.55 H, 10.71 Found C, 76.38 H, 10.67 67 Anal. For C₂₂H₃₆O₂ Calcd. C, 79.46 H, 10.91 Found C, 79.62 H, 11.00 68 Anal. For C₂₂H₃₆O₂ Calcd. C, 79.46 H, 10.91 Found C, 79.60 H, 10.96 69 Anal. For C₂₃H₃₈O₂ Calcd. C, 79.71 H, 11.05 Found C, 80.04 H, 11.20 70 Anal. For C₂₃H₃₈O₂ Calcd. C, 79.71 H, 11.05 Found C, 79.80 H, 10.89 71 Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 79.88 H, 10.15 72 Anal. For C₂₂H₃₄O₂ Calcd. C, 79.95 H, 10.37 Found C, 80.16 H, 10.18 73 Anal. For C₂₃H₃₆O₂ Calcd. C, 80.18 H, 10.53 Found C, 80.38 H, 10.63 74 Anal. For C₂₃H₃₆O₂ Calcd. C, 80.18 H, 10.53 Found C, 79.96 H, 10.67 77 Anal. For C₂₆H₄₂O₃ Calcd. C, 77.56 H, 10.51 Found C, 77.70 H, 10.62 78 Anal. For C₂₆H₄₂O₃ Calcd. C, 77.56 H, 10.51 Found C, 77.76 H, 10.70 79 Anal. For C₂₄H₃₈O₂ Calcd. C, 80.39 H, 10.68 Found C, 80.50 H, 10.88 80 Anal. For C₂₄H₃₈O₂ Calcd. C, 80.39 H, 10.68 Found C, 80.25 H, 10.47 82 Anal. For C₂₆H₄₀O₃ Calcd. C, 77.95 H, 10.06 Found C, 77.84 H, 10.19 83 Anal. For C₂₄H₃₆O₂ Calcd. C, 80.85 H, 10.18 Found C, 81.02 H, 10.37 86 Anal. For C₂₃H₃₄O₃ Calcd. C, 77.05 H, 9.56 Found C, 77.06 H, 9.67 88 Anal. For C₂₈H₃₆O₃ Calcd. C, 79.96 H, 8.63 Found C, 79.98 H, 8.80 89 Anal. For C₂₁H₃₂O₂ Calcd. C, 79.70 H, 10.19 Found C, 79.69 H, 9.94 94 Anal. For C₂₁H₃₀O₂ Calcd. C, 80.21 H, 9.62 Found C, 80.16 H, 9.66 95 Anal. For C₂₁H₂₉BrO₂ Calcd. C, 64.12 H, 7.43 Found C, 64.25 H, 7.40 96 Anal. For C₂₃H₃₃NO Calcd. C, 81.37 H, 9.80 N, 4.13 Found C, 81.16 H, 9.67 N, 3.95 97 Anal. For C₂₃H₃₃NO Calcd. C, 81.37 H, 9.80 N, 4.13 Found C, 81.51 H, 10.00 N, 4.16 

What is claimed is:
 1. A method of treating convulsions related to GABA_(A) receptor function in a mammal, said method comprising administering to a mammal in need thereof a therapeutically effective amount of a pharmaceutical composition containing a steroid or D-homosteroid and at least one pharmaceutically acceptable carrier, wherein the steroid or D-homosteroid is a compound of Formula (A)

wherein R₂ is selected from the group consisting of hydrogen, alkoxy, and substituted or unsubstituted morpholine R_(3a) is hydroxyl or carboxyl; R_(3b) is hydrogen, alkyl, alkenyl, or alkynyl optionally substituted with halo, hydroxyl, or substituted or unsubstituted aryl; R₅ is α- or β-hydrogen; R₁₀ is hydrogen or C₁₋₄ alkyl; R₁₅ is hydrogen or oxo; R₆, R₁₁ and R₁₂ are independently hydrogen or oxo; L_(3a) is selected from the group consisting of a bond, C₁₋₃ alkyl, heterosubstituted C₁₋₃ alkyl, or alkoxy; X₄-X₅-X₆ is selected from the group consisting of

X₉-X₁₁-X₁₂ is selected from the group consisting of

X₄₀ is a bond or a carbon atom; and E is a 5- or 6-membered carbocyclic ring in the β-configuration in relation to the C and D rings, comprising a hydrogen bond acceptor and (i) the carbons at C(13) and C(17) when X₄₀ is a bond, or (ii) the carbons at C(13) and C(17a) when X₄₀ is carbon.
 2. The method of claim 1 wherein the hydrogen bond acceptor is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl.
 3. The method of claim 2 wherein the E ring hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, epoxide, an E ring alkene bond, and combinations thereof.
 4. The method of claim 1 wherein the C(3) substituent is a carboxyl in the α-configuration or a sulfate.
 5. The method of claim 2 wherein L_(3a) is selected from the group consisting of a bond, methylene, ethylene, methoxy, and ethoxy and R_(3a) is hydroxyl.
 6. The method of claim 2 wherein X₄-X₅-X₆ is

X₉-X₁₁-X₁₂ is


7. The method of claim 1 wherein R₂ is hydrogen; R_(3b) is hydrogen; R₁₀ is hydrogen or β-methyl; R₁₅ is hydrogen; R₆, R₁₁ and R₁₂ are independently hydrogen or oxo; L_(3a) is a bond; and X₄₀ is a bond.
 8. The method of claim 7 wherein the hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, epoxide, an E ring alkene bond, and combinations thereof.
 9. The method of claim 1 wherein the steroid or D-homosteroid is Formula (B)

wherein R_(3a) is hydroxyl or carboxyl; and R₅ is α- or β-hydrogen.
 10. The method of claim 9 wherein the E ring comprises a hydrogen bond acceptor selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl.
 11. The method of claim 10 wherein the hydrogen bond acceptor is selected from the group consisting of keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, epoxide, and combinations thereof.
 12. The method of claim 10 wherein the hydrogen bond acceptor comprises an E ring alkene bond.
 13. The method of claim 9 wherein the steroid or D-homosteroid is Formula (C)

wherein R₅ is α- or β-hydrogen; R₅₀ is selected from the group consisting of hydrogen, keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl, provided that when R₅₀ is hydrogen at least one pair of E ring atoms share a double bond; and E is a 6-membered carbocyclic ring wherein the dashed lines represent optional double bonds provided E comprises no more than 2 double bonds and provided each carbon ring atom of E is sp² or sp³ hybridized.
 14. The method of claim 13 wherein R₅₀ is selected from the group consisting of hydrogen, keto, cyano, methylene, methoxy, acetyl, ═CHCN, ═CHC(O)CH₃, epoxide, and combinations thereof, provided that when R₅₀ is hydrogen at least one pair of E ring atoms share a double bond.
 15. The method of claim 9 wherein the steroid or D-homosteroid is Formula (D)

wherein R₅ is α- or β-hydrogen; R₅₀ is selected from the group consisting of hydrogen, keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl, provided that when R₅₀ is hydrogen at least one pair of E ring atoms share a double bond; and E is a 5-membered carbocyclic ring wherein the dashed lines represent optional double bonds provided E comprises no more than 2 double bonds and provided each carbon ring atom of E is sp² or sp^(a) hybridized.
 16. A method of treating convulsions related to GABA_(A) receptor function in a mammal, said method comprising administering to a mammal in need thereof a therapeutically effective amount of a pharmaceutical composition containing a steroid or D-homosteroid and at least one pharmaceutically acceptable carrier, wherein said steroid or D-homo steroid is selected from the group consisting of


17. A method of treating convulsions related to GABA_(A) receptor function in a mammal, said method comprising administering a therapeutically effective amount of a pharmaceutical composition containing a steroid or D-homosteroid and at least one pharmaceutically acceptable carrier, wherein said steroid or D-homosteroid is a compound of Formula (A)

wherein R₂ is selected from the group consisting of hydrogen, alkoxy, and substituted or unsubstituted morpholine R_(3a) is selected from the group consisting of sulfate, phosphate, and phosphonate; R_(3b) is hydrogen, alkyl, alkenyl, or alkynyl optionally substituted with halo, hydroxyl, or substituted or unsubstituted aryl; R₅ is α- or β-hydrogen; R₁₀ is hydrogen or C₁₋₄ alkyl; R₁₅ is hydrogen or oxo; R₆, R₁₁ and R₁₂ are independently hydrogen or oxo; L_(3a) is selected from the group consisting of a bond, C₁₋₃ alkyl, heterosubstituted C₁₋₃ alkyl, or alkoxy; X₄-X₅-X₆ is selected from the group consisting of

X₉-X₁₁-X₁₂ is selected from the group consisting of

X₄₀ is a bond or a carbon atom; and E is a 5- or 6-membered carbocyclic ring in the β-configuration in relation to the C and D rings, comprising a hydrogen bond acceptor and (i) the carbons at C(13) and C(17) when X₄₀ is a bond, or (ii) the carbons at C(13) and C(17a) when X₄₀ is carbon.
 18. The method of claim 17 wherein L_(3a) is a bond and R_(3a) is in the β-configuration.
 19. The method of claim 17 wherein the hydrogen bond acceptor is selected from the group consisting of keto, cyano, acyl, ═CHX₁, —OX₂, —C(O)X₂, epoxide, an E ring alkene bond, and combinations thereof; X₁ is selected from the group consisting of hydrogen, cyano, hydrocarbyl, substituted hydrocarbyl and acyl; and X₂ is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and acyl. 